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- markus@cvs.openbsd.org 2009/11/11 21:37:03
[openssh-git.git] / channels.c
blob94939239022df3867337d554afc3d14a39c28af0
1 /* $OpenBSD: channels.c,v 1.299 2009/11/11 21:37:03 markus Exp $ */
2 /*
3 * Author: Tatu Ylonen <ylo@cs.hut.fi>
4 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
5 * All rights reserved
6 * This file contains functions for generic socket connection forwarding.
7 * There is also code for initiating connection forwarding for X11 connections,
8 * arbitrary tcp/ip connections, and the authentication agent connection.
9 *
10 * As far as I am concerned, the code I have written for this software
11 * can be used freely for any purpose. Any derived versions of this
12 * software must be clearly marked as such, and if the derived work is
13 * incompatible with the protocol description in the RFC file, it must be
14 * called by a name other than "ssh" or "Secure Shell".
15 *
16 * SSH2 support added by Markus Friedl.
17 * Copyright (c) 1999, 2000, 2001, 2002 Markus Friedl. All rights reserved.
18 * Copyright (c) 1999 Dug Song. All rights reserved.
19 * Copyright (c) 1999 Theo de Raadt. All rights reserved.
20 *
21 * Redistribution and use in source and binary forms, with or without
22 * modification, are permitted provided that the following conditions
23 * are met:
24 * 1. Redistributions of source code must retain the above copyright
25 * notice, this list of conditions and the following disclaimer.
26 * 2. Redistributions in binary form must reproduce the above copyright
27 * notice, this list of conditions and the following disclaimer in the
28 * documentation and/or other materials provided with the distribution.
29 *
30 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
31 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
32 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
33 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
34 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
35 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
36 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
37 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
38 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
39 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
40 */
41
42 #include "includes.h"
43
44 #include <sys/types.h>
45 #include <sys/ioctl.h>
46 #include <sys/un.h>
47 #include <sys/socket.h>
48 #ifdef HAVE_SYS_TIME_H
49 # include <sys/time.h>
50 #endif
51
52 #include <netinet/in.h>
53 #include <arpa/inet.h>
54
55 #include <errno.h>
56 #include <fcntl.h>
57 #include <netdb.h>
58 #include <stdio.h>
59 #include <stdlib.h>
60 #include <string.h>
61 #include <termios.h>
62 #include <unistd.h>
63 #include <stdarg.h>
64
65 #include "openbsd-compat/sys-queue.h"
66 #include "xmalloc.h"
67 #include "ssh.h"
68 #include "ssh1.h"
69 #include "ssh2.h"
70 #include "packet.h"
71 #include "log.h"
72 #include "misc.h"
73 #include "buffer.h"
74 #include "channels.h"
75 #include "compat.h"
76 #include "canohost.h"
77 #include "key.h"
78 #include "authfd.h"
79 #include "pathnames.h"
80
81 /* -- channel core */
82
83 /*
84 * Pointer to an array containing all allocated channels. The array is
85 * dynamically extended as needed.
86 */
87 static Channel **channels = NULL;
88
89 /*
90 * Size of the channel array. All slots of the array must always be
91 * initialized (at least the type field); unused slots set to NULL
92 */
93 static u_int channels_alloc = 0;
94
95 /*
96 * Maximum file descriptor value used in any of the channels. This is
97 * updated in channel_new.
98 */
99 static int channel_max_fd = 0;
100
101
102 /* -- tcp forwarding */
103
104 /*
105 * Data structure for storing which hosts are permitted for forward requests.
106 * The local sides of any remote forwards are stored in this array to prevent
107 * a corrupt remote server from accessing arbitrary TCP/IP ports on our local
108 * network (which might be behind a firewall).
109 */
110 typedef struct {
111 char *host_to_connect; /* Connect to 'host'. */
112 u_short port_to_connect; /* Connect to 'port'. */
113 u_short listen_port; /* Remote side should listen port number. */
114 } ForwardPermission;
115
116 /* List of all permitted host/port pairs to connect by the user. */
117 static ForwardPermission permitted_opens[SSH_MAX_FORWARDS_PER_DIRECTION];
118
119 /* List of all permitted host/port pairs to connect by the admin. */
120 static ForwardPermission permitted_adm_opens[SSH_MAX_FORWARDS_PER_DIRECTION];
121
122 /* Number of permitted host/port pairs in the array permitted by the user. */
123 static int num_permitted_opens = 0;
124
125 /* Number of permitted host/port pair in the array permitted by the admin. */
126 static int num_adm_permitted_opens = 0;
127
128 /*
129 * If this is true, all opens are permitted. This is the case on the server
130 * on which we have to trust the client anyway, and the user could do
131 * anything after logging in anyway.
132 */
133 static int all_opens_permitted = 0;
134
135
136 /* -- X11 forwarding */
137
138 /* Maximum number of fake X11 displays to try. */
139 #define MAX_DISPLAYS 1000
140
141 /* Saved X11 local (client) display. */
142 static char *x11_saved_display = NULL;
143
144 /* Saved X11 authentication protocol name. */
145 static char *x11_saved_proto = NULL;
146
147 /* Saved X11 authentication data. This is the real data. */
148 static char *x11_saved_data = NULL;
149 static u_int x11_saved_data_len = 0;
150
151 /*
152 * Fake X11 authentication data. This is what the server will be sending us;
153 * we should replace any occurrences of this by the real data.
154 */
155 static u_char *x11_fake_data = NULL;
156 static u_int x11_fake_data_len;
157
158
159 /* -- agent forwarding */
160
161 #define NUM_SOCKS 10
162
163 /* AF_UNSPEC or AF_INET or AF_INET6 */
164 static int IPv4or6 = AF_UNSPEC;
165
166 /* Set the routing domain a.k.a. VRF */
167 static int channel_rdomain = -1;
168
169 /* helper */
170 static void port_open_helper(Channel *c, char *rtype);
171
172 /* non-blocking connect helpers */
173 static int connect_next(struct channel_connect *);
174 static void channel_connect_ctx_free(struct channel_connect *);
175
176 /* -- channel core */
177
178 Channel *
179 channel_by_id(int id)
180 {
181 Channel *c;
182
183 if (id < 0 || (u_int)id >= channels_alloc) {
184 logit("channel_by_id: %d: bad id", id);
185 return NULL;
186 }
187 c = channels[id];
188 if (c == NULL) {
189 logit("channel_by_id: %d: bad id: channel free", id);
190 return NULL;
191 }
192 return c;
193 }
194
195 /*
196 * Returns the channel if it is allowed to receive protocol messages.
197 * Private channels, like listening sockets, may not receive messages.
198 */
199 Channel *
200 channel_lookup(int id)
201 {
202 Channel *c;
203
204 if ((c = channel_by_id(id)) == NULL)
205 return (NULL);
206
207 switch (c->type) {
208 case SSH_CHANNEL_X11_OPEN:
209 case SSH_CHANNEL_LARVAL:
210 case SSH_CHANNEL_CONNECTING:
211 case SSH_CHANNEL_DYNAMIC:
212 case SSH_CHANNEL_OPENING:
213 case SSH_CHANNEL_OPEN:
214 case SSH_CHANNEL_INPUT_DRAINING:
215 case SSH_CHANNEL_OUTPUT_DRAINING:
216 return (c);
217 }
218 logit("Non-public channel %d, type %d.", id, c->type);
219 return (NULL);
220 }
221
222 /*
223 * Register filedescriptors for a channel, used when allocating a channel or
224 * when the channel consumer/producer is ready, e.g. shell exec'd
225 */
226 static void
227 channel_register_fds(Channel *c, int rfd, int wfd, int efd,
228 int extusage, int nonblock, int is_tty)
229 {
230 /* Update the maximum file descriptor value. */
231 channel_max_fd = MAX(channel_max_fd, rfd);
232 channel_max_fd = MAX(channel_max_fd, wfd);
233 channel_max_fd = MAX(channel_max_fd, efd);
234
235 if (rfd != -1)
236 fcntl(rfd, F_SETFD, FD_CLOEXEC);
237 if (wfd != -1 && wfd != rfd)
238 fcntl(wfd, F_SETFD, FD_CLOEXEC);
239 if (efd != -1 && efd != rfd && efd != wfd)
240 fcntl(efd, F_SETFD, FD_CLOEXEC);
241
242 c->rfd = rfd;
243 c->wfd = wfd;
244 c->sock = (rfd == wfd) ? rfd : -1;
245 c->ctl_fd = -1; /* XXX: set elsewhere */
246 c->efd = efd;
247 c->extended_usage = extusage;
248
249 if ((c->isatty = is_tty) != 0)
250 debug2("channel %d: rfd %d isatty", c->self, c->rfd);
251 c->wfd_isatty = is_tty || isatty(c->wfd);
252
253 /* enable nonblocking mode */
254 if (nonblock) {
255 if (rfd != -1)
256 set_nonblock(rfd);
257 if (wfd != -1)
258 set_nonblock(wfd);
259 if (efd != -1)
260 set_nonblock(efd);
261 }
262 }
263
264 /*
265 * Allocate a new channel object and set its type and socket. This will cause
266 * remote_name to be freed.
267 */
268 Channel *
269 channel_new(char *ctype, int type, int rfd, int wfd, int efd,
270 u_int window, u_int maxpack, int extusage, char *remote_name, int nonblock)
271 {
272 int found;
273 u_int i;
274 Channel *c;
275
276 /* Do initial allocation if this is the first call. */
277 if (channels_alloc == 0) {
278 channels_alloc = 10;
279 channels = xcalloc(channels_alloc, sizeof(Channel *));
280 for (i = 0; i < channels_alloc; i++)
281 channels[i] = NULL;
282 }
283 /* Try to find a free slot where to put the new channel. */
284 for (found = -1, i = 0; i < channels_alloc; i++)
285 if (channels[i] == NULL) {
286 /* Found a free slot. */
287 found = (int)i;
288 break;
289 }
290 if (found < 0) {
291 /* There are no free slots. Take last+1 slot and expand the array. */
292 found = channels_alloc;
293 if (channels_alloc > 10000)
294 fatal("channel_new: internal error: channels_alloc %d "
295 "too big.", channels_alloc);
296 channels = xrealloc(channels, channels_alloc + 10,
297 sizeof(Channel *));
298 channels_alloc += 10;
299 debug2("channel: expanding %d", channels_alloc);
300 for (i = found; i < channels_alloc; i++)
301 channels[i] = NULL;
302 }
303 /* Initialize and return new channel. */
304 c = channels[found] = xcalloc(1, sizeof(Channel));
305 buffer_init(&c->input);
306 buffer_init(&c->output);
307 buffer_init(&c->extended);
308 c->path = NULL;
309 c->ostate = CHAN_OUTPUT_OPEN;
310 c->istate = CHAN_INPUT_OPEN;
311 c->flags = 0;
312 channel_register_fds(c, rfd, wfd, efd, extusage, nonblock, 0);
313 c->self = found;
314 c->type = type;
315 c->ctype = ctype;
316 c->local_window = window;
317 c->local_window_max = window;
318 c->local_consumed = 0;
319 c->local_maxpacket = maxpack;
320 c->remote_id = -1;
321 c->remote_name = xstrdup(remote_name);
322 c->remote_window = 0;
323 c->remote_maxpacket = 0;
324 c->force_drain = 0;
325 c->single_connection = 0;
326 c->detach_user = NULL;
327 c->detach_close = 0;
328 c->open_confirm = NULL;
329 c->open_confirm_ctx = NULL;
330 c->input_filter = NULL;
331 c->output_filter = NULL;
332 c->filter_ctx = NULL;
333 c->filter_cleanup = NULL;
334 c->delayed = 1; /* prevent call to channel_post handler */
335 TAILQ_INIT(&c->status_confirms);
336 debug("channel %d: new [%s]", found, remote_name);
337 return c;
338 }
339
340 static int
341 channel_find_maxfd(void)
342 {
343 u_int i;
344 int max = 0;
345 Channel *c;
346
347 for (i = 0; i < channels_alloc; i++) {
348 c = channels[i];
349 if (c != NULL) {
350 max = MAX(max, c->rfd);
351 max = MAX(max, c->wfd);
352 max = MAX(max, c->efd);
353 }
354 }
355 return max;
356 }
357
358 int
359 channel_close_fd(int *fdp)
360 {
361 int ret = 0, fd = *fdp;
362
363 if (fd != -1) {
364 ret = close(fd);
365 *fdp = -1;
366 if (fd == channel_max_fd)
367 channel_max_fd = channel_find_maxfd();
368 }
369 return ret;
370 }
371
372 /* Close all channel fd/socket. */
373 static void
374 channel_close_fds(Channel *c)
375 {
376 debug3("channel %d: close_fds r %d w %d e %d c %d",
377 c->self, c->rfd, c->wfd, c->efd, c->ctl_fd);
378
379 channel_close_fd(&c->sock);
380 channel_close_fd(&c->ctl_fd);
381 channel_close_fd(&c->rfd);
382 channel_close_fd(&c->wfd);
383 channel_close_fd(&c->efd);
384 }
385
386 /* Free the channel and close its fd/socket. */
387 void
388 channel_free(Channel *c)
389 {
390 char *s;
391 u_int i, n;
392 struct channel_confirm *cc;
393
394 for (n = 0, i = 0; i < channels_alloc; i++)
395 if (channels[i])
396 n++;
397 debug("channel %d: free: %s, nchannels %u", c->self,
398 c->remote_name ? c->remote_name : "???", n);
399
400 s = channel_open_message();
401 debug3("channel %d: status: %s", c->self, s);
402 xfree(s);
403
404 if (c->sock != -1)
405 shutdown(c->sock, SHUT_RDWR);
406 if (c->ctl_fd != -1)
407 shutdown(c->ctl_fd, SHUT_RDWR);
408 channel_close_fds(c);
409 buffer_free(&c->input);
410 buffer_free(&c->output);
411 buffer_free(&c->extended);
412 if (c->remote_name) {
413 xfree(c->remote_name);
414 c->remote_name = NULL;
415 }
416 if (c->path) {
417 xfree(c->path);
418 c->path = NULL;
419 }
420 while ((cc = TAILQ_FIRST(&c->status_confirms)) != NULL) {
421 if (cc->abandon_cb != NULL)
422 cc->abandon_cb(c, cc->ctx);
423 TAILQ_REMOVE(&c->status_confirms, cc, entry);
424 bzero(cc, sizeof(*cc));
425 xfree(cc);
426 }
427 if (c->filter_cleanup != NULL && c->filter_ctx != NULL)
428 c->filter_cleanup(c->self, c->filter_ctx);
429 channels[c->self] = NULL;
430 xfree(c);
431 }
432
433 void
434 channel_free_all(void)
435 {
436 u_int i;
437
438 for (i = 0; i < channels_alloc; i++)
439 if (channels[i] != NULL)
440 channel_free(channels[i]);
441 }
442
443 /*
444 * Closes the sockets/fds of all channels. This is used to close extra file
445 * descriptors after a fork.
446 */
447 void
448 channel_close_all(void)
449 {
450 u_int i;
451
452 for (i = 0; i < channels_alloc; i++)
453 if (channels[i] != NULL)
454 channel_close_fds(channels[i]);
455 }
456
457 /*
458 * Stop listening to channels.
459 */
460 void
461 channel_stop_listening(void)
462 {
463 u_int i;
464 Channel *c;
465
466 for (i = 0; i < channels_alloc; i++) {
467 c = channels[i];
468 if (c != NULL) {
469 switch (c->type) {
470 case SSH_CHANNEL_AUTH_SOCKET:
471 case SSH_CHANNEL_PORT_LISTENER:
472 case SSH_CHANNEL_RPORT_LISTENER:
473 case SSH_CHANNEL_X11_LISTENER:
474 channel_close_fd(&c->sock);
475 channel_free(c);
476 break;
477 }
478 }
479 }
480 }
481
482 /*
483 * Returns true if no channel has too much buffered data, and false if one or
484 * more channel is overfull.
485 */
486 int
487 channel_not_very_much_buffered_data(void)
488 {
489 u_int i;
490 Channel *c;
491
492 for (i = 0; i < channels_alloc; i++) {
493 c = channels[i];
494 if (c != NULL && c->type == SSH_CHANNEL_OPEN) {
495 #if 0
496 if (!compat20 &&
497 buffer_len(&c->input) > packet_get_maxsize()) {
498 debug2("channel %d: big input buffer %d",
499 c->self, buffer_len(&c->input));
500 return 0;
501 }
502 #endif
503 if (buffer_len(&c->output) > packet_get_maxsize()) {
504 debug2("channel %d: big output buffer %u > %u",
505 c->self, buffer_len(&c->output),
506 packet_get_maxsize());
507 return 0;
508 }
509 }
510 }
511 return 1;
512 }
513
514 /* Returns true if any channel is still open. */
515 int
516 channel_still_open(void)
517 {
518 u_int i;
519 Channel *c;
520
521 for (i = 0; i < channels_alloc; i++) {
522 c = channels[i];
523 if (c == NULL)
524 continue;
525 switch (c->type) {
526 case SSH_CHANNEL_X11_LISTENER:
527 case SSH_CHANNEL_PORT_LISTENER:
528 case SSH_CHANNEL_RPORT_LISTENER:
529 case SSH_CHANNEL_CLOSED:
530 case SSH_CHANNEL_AUTH_SOCKET:
531 case SSH_CHANNEL_DYNAMIC:
532 case SSH_CHANNEL_CONNECTING:
533 case SSH_CHANNEL_ZOMBIE:
534 continue;
535 case SSH_CHANNEL_LARVAL:
536 if (!compat20)
537 fatal("cannot happen: SSH_CHANNEL_LARVAL");
538 continue;
539 case SSH_CHANNEL_OPENING:
540 case SSH_CHANNEL_OPEN:
541 case SSH_CHANNEL_X11_OPEN:
542 return 1;
543 case SSH_CHANNEL_INPUT_DRAINING:
544 case SSH_CHANNEL_OUTPUT_DRAINING:
545 if (!compat13)
546 fatal("cannot happen: OUT_DRAIN");
547 return 1;
548 default:
549 fatal("channel_still_open: bad channel type %d", c->type);
550 /* NOTREACHED */
551 }
552 }
553 return 0;
554 }
555
556 /* Returns the id of an open channel suitable for keepaliving */
557 int
558 channel_find_open(void)
559 {
560 u_int i;
561 Channel *c;
562
563 for (i = 0; i < channels_alloc; i++) {
564 c = channels[i];
565 if (c == NULL || c->remote_id < 0)
566 continue;
567 switch (c->type) {
568 case SSH_CHANNEL_CLOSED:
569 case SSH_CHANNEL_DYNAMIC:
570 case SSH_CHANNEL_X11_LISTENER:
571 case SSH_CHANNEL_PORT_LISTENER:
572 case SSH_CHANNEL_RPORT_LISTENER:
573 case SSH_CHANNEL_OPENING:
574 case SSH_CHANNEL_CONNECTING:
575 case SSH_CHANNEL_ZOMBIE:
576 continue;
577 case SSH_CHANNEL_LARVAL:
578 case SSH_CHANNEL_AUTH_SOCKET:
579 case SSH_CHANNEL_OPEN:
580 case SSH_CHANNEL_X11_OPEN:
581 return i;
582 case SSH_CHANNEL_INPUT_DRAINING:
583 case SSH_CHANNEL_OUTPUT_DRAINING:
584 if (!compat13)
585 fatal("cannot happen: OUT_DRAIN");
586 return i;
587 default:
588 fatal("channel_find_open: bad channel type %d", c->type);
589 /* NOTREACHED */
590 }
591 }
592 return -1;
593 }
594
595
596 /*
597 * Returns a message describing the currently open forwarded connections,
598 * suitable for sending to the client. The message contains crlf pairs for
599 * newlines.
600 */
601 char *
602 channel_open_message(void)
603 {
604 Buffer buffer;
605 Channel *c;
606 char buf[1024], *cp;
607 u_int i;
608
609 buffer_init(&buffer);
610 snprintf(buf, sizeof buf, "The following connections are open:\r\n");
611 buffer_append(&buffer, buf, strlen(buf));
612 for (i = 0; i < channels_alloc; i++) {
613 c = channels[i];
614 if (c == NULL)
615 continue;
616 switch (c->type) {
617 case SSH_CHANNEL_X11_LISTENER:
618 case SSH_CHANNEL_PORT_LISTENER:
619 case SSH_CHANNEL_RPORT_LISTENER:
620 case SSH_CHANNEL_CLOSED:
621 case SSH_CHANNEL_AUTH_SOCKET:
622 case SSH_CHANNEL_ZOMBIE:
623 continue;
624 case SSH_CHANNEL_LARVAL:
625 case SSH_CHANNEL_OPENING:
626 case SSH_CHANNEL_CONNECTING:
627 case SSH_CHANNEL_DYNAMIC:
628 case SSH_CHANNEL_OPEN:
629 case SSH_CHANNEL_X11_OPEN:
630 case SSH_CHANNEL_INPUT_DRAINING:
631 case SSH_CHANNEL_OUTPUT_DRAINING:
632 snprintf(buf, sizeof buf,
633 " #%d %.300s (t%d r%d i%d/%d o%d/%d fd %d/%d cfd %d)\r\n",
634 c->self, c->remote_name,
635 c->type, c->remote_id,
636 c->istate, buffer_len(&c->input),
637 c->ostate, buffer_len(&c->output),
638 c->rfd, c->wfd, c->ctl_fd);
639 buffer_append(&buffer, buf, strlen(buf));
640 continue;
641 default:
642 fatal("channel_open_message: bad channel type %d", c->type);
643 /* NOTREACHED */
644 }
645 }
646 buffer_append(&buffer, "\0", 1);
647 cp = xstrdup(buffer_ptr(&buffer));
648 buffer_free(&buffer);
649 return cp;
650 }
651
652 void
653 channel_send_open(int id)
654 {
655 Channel *c = channel_lookup(id);
656
657 if (c == NULL) {
658 logit("channel_send_open: %d: bad id", id);
659 return;
660 }
661 debug2("channel %d: send open", id);
662 packet_start(SSH2_MSG_CHANNEL_OPEN);
663 packet_put_cstring(c->ctype);
664 packet_put_int(c->self);
665 packet_put_int(c->local_window);
666 packet_put_int(c->local_maxpacket);
667 packet_send();
668 }
669
670 void
671 channel_request_start(int id, char *service, int wantconfirm)
672 {
673 Channel *c = channel_lookup(id);
674
675 if (c == NULL) {
676 logit("channel_request_start: %d: unknown channel id", id);
677 return;
678 }
679 debug2("channel %d: request %s confirm %d", id, service, wantconfirm);
680 packet_start(SSH2_MSG_CHANNEL_REQUEST);
681 packet_put_int(c->remote_id);
682 packet_put_cstring(service);
683 packet_put_char(wantconfirm);
684 }
685
686 void
687 channel_register_status_confirm(int id, channel_confirm_cb *cb,
688 channel_confirm_abandon_cb *abandon_cb, void *ctx)
689 {
690 struct channel_confirm *cc;
691 Channel *c;
692
693 if ((c = channel_lookup(id)) == NULL)
694 fatal("channel_register_expect: %d: bad id", id);
695
696 cc = xmalloc(sizeof(*cc));
697 cc->cb = cb;
698 cc->abandon_cb = abandon_cb;
699 cc->ctx = ctx;
700 TAILQ_INSERT_TAIL(&c->status_confirms, cc, entry);
701 }
702
703 void
704 channel_register_open_confirm(int id, channel_callback_fn *fn, void *ctx)
705 {
706 Channel *c = channel_lookup(id);
707
708 if (c == NULL) {
709 logit("channel_register_open_confirm: %d: bad id", id);
710 return;
711 }
712 c->open_confirm = fn;
713 c->open_confirm_ctx = ctx;
714 }
715
716 void
717 channel_register_cleanup(int id, channel_callback_fn *fn, int do_close)
718 {
719 Channel *c = channel_by_id(id);
720
721 if (c == NULL) {
722 logit("channel_register_cleanup: %d: bad id", id);
723 return;
724 }
725 c->detach_user = fn;
726 c->detach_close = do_close;
727 }
728
729 void
730 channel_cancel_cleanup(int id)
731 {
732 Channel *c = channel_by_id(id);
733
734 if (c == NULL) {
735 logit("channel_cancel_cleanup: %d: bad id", id);
736 return;
737 }
738 c->detach_user = NULL;
739 c->detach_close = 0;
740 }
741
742 void
743 channel_register_filter(int id, channel_infilter_fn *ifn,
744 channel_outfilter_fn *ofn, channel_filter_cleanup_fn *cfn, void *ctx)
745 {
746 Channel *c = channel_lookup(id);
747
748 if (c == NULL) {
749 logit("channel_register_filter: %d: bad id", id);
750 return;
751 }
752 c->input_filter = ifn;
753 c->output_filter = ofn;
754 c->filter_ctx = ctx;
755 c->filter_cleanup = cfn;
756 }
757
758 void
759 channel_set_fds(int id, int rfd, int wfd, int efd,
760 int extusage, int nonblock, int is_tty, u_int window_max)
761 {
762 Channel *c = channel_lookup(id);
763
764 if (c == NULL || c->type != SSH_CHANNEL_LARVAL)
765 fatal("channel_activate for non-larval channel %d.", id);
766 channel_register_fds(c, rfd, wfd, efd, extusage, nonblock, is_tty);
767 c->type = SSH_CHANNEL_OPEN;
768 c->local_window = c->local_window_max = window_max;
769 packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
770 packet_put_int(c->remote_id);
771 packet_put_int(c->local_window);
772 packet_send();
773 }
774
775 /*
776 * 'channel_pre*' are called just before select() to add any bits relevant to
777 * channels in the select bitmasks.
778 */
779 /*
780 * 'channel_post*': perform any appropriate operations for channels which
781 * have events pending.
782 */
783 typedef void chan_fn(Channel *c, fd_set *readset, fd_set *writeset);
784 chan_fn *channel_pre[SSH_CHANNEL_MAX_TYPE];
785 chan_fn *channel_post[SSH_CHANNEL_MAX_TYPE];
786
787 /* ARGSUSED */
788 static void
789 channel_pre_listener(Channel *c, fd_set *readset, fd_set *writeset)
790 {
791 FD_SET(c->sock, readset);
792 }
793
794 /* ARGSUSED */
795 static void
796 channel_pre_connecting(Channel *c, fd_set *readset, fd_set *writeset)
797 {
798 debug3("channel %d: waiting for connection", c->self);
799 FD_SET(c->sock, writeset);
800 }
801
802 static void
803 channel_pre_open_13(Channel *c, fd_set *readset, fd_set *writeset)
804 {
805 if (buffer_len(&c->input) < packet_get_maxsize())
806 FD_SET(c->sock, readset);
807 if (buffer_len(&c->output) > 0)
808 FD_SET(c->sock, writeset);
809 }
810
811 static void
812 channel_pre_open(Channel *c, fd_set *readset, fd_set *writeset)
813 {
814 u_int limit = compat20 ? c->remote_window : packet_get_maxsize();
815
816 if (c->istate == CHAN_INPUT_OPEN &&
817 limit > 0 &&
818 buffer_len(&c->input) < limit &&
819 buffer_check_alloc(&c->input, CHAN_RBUF))
820 FD_SET(c->rfd, readset);
821 if (c->ostate == CHAN_OUTPUT_OPEN ||
822 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
823 if (buffer_len(&c->output) > 0) {
824 FD_SET(c->wfd, writeset);
825 } else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
826 if (CHANNEL_EFD_OUTPUT_ACTIVE(c))
827 debug2("channel %d: obuf_empty delayed efd %d/(%d)",
828 c->self, c->efd, buffer_len(&c->extended));
829 else
830 chan_obuf_empty(c);
831 }
832 }
833 /** XXX check close conditions, too */
834 if (compat20 && c->efd != -1 &&
835 !(c->istate == CHAN_INPUT_CLOSED && c->ostate == CHAN_OUTPUT_CLOSED)) {
836 if (c->extended_usage == CHAN_EXTENDED_WRITE &&
837 buffer_len(&c->extended) > 0)
838 FD_SET(c->efd, writeset);
839 else if (!(c->flags & CHAN_EOF_SENT) &&
840 c->extended_usage == CHAN_EXTENDED_READ &&
841 buffer_len(&c->extended) < c->remote_window)
842 FD_SET(c->efd, readset);
843 }
844 /* XXX: What about efd? races? */
845 if (compat20 && c->ctl_fd != -1 &&
846 c->istate == CHAN_INPUT_OPEN && c->ostate == CHAN_OUTPUT_OPEN)
847 FD_SET(c->ctl_fd, readset);
848 }
849
850 /* ARGSUSED */
851 static void
852 channel_pre_input_draining(Channel *c, fd_set *readset, fd_set *writeset)
853 {
854 if (buffer_len(&c->input) == 0) {
855 packet_start(SSH_MSG_CHANNEL_CLOSE);
856 packet_put_int(c->remote_id);
857 packet_send();
858 c->type = SSH_CHANNEL_CLOSED;
859 debug2("channel %d: closing after input drain.", c->self);
860 }
861 }
862
863 /* ARGSUSED */
864 static void
865 channel_pre_output_draining(Channel *c, fd_set *readset, fd_set *writeset)
866 {
867 if (buffer_len(&c->output) == 0)
868 chan_mark_dead(c);
869 else
870 FD_SET(c->sock, writeset);
871 }
872
873 /*
874 * This is a special state for X11 authentication spoofing. An opened X11
875 * connection (when authentication spoofing is being done) remains in this
876 * state until the first packet has been completely read. The authentication
877 * data in that packet is then substituted by the real data if it matches the
878 * fake data, and the channel is put into normal mode.
879 * XXX All this happens at the client side.
880 * Returns: 0 = need more data, -1 = wrong cookie, 1 = ok
881 */
882 static int
883 x11_open_helper(Buffer *b)
884 {
885 u_char *ucp;
886 u_int proto_len, data_len;
887
888 /* Check if the fixed size part of the packet is in buffer. */
889 if (buffer_len(b) < 12)
890 return 0;
891
892 /* Parse the lengths of variable-length fields. */
893 ucp = buffer_ptr(b);
894 if (ucp[0] == 0x42) { /* Byte order MSB first. */
895 proto_len = 256 * ucp[6] + ucp[7];
896 data_len = 256 * ucp[8] + ucp[9];
897 } else if (ucp[0] == 0x6c) { /* Byte order LSB first. */
898 proto_len = ucp[6] + 256 * ucp[7];
899 data_len = ucp[8] + 256 * ucp[9];
900 } else {
901 debug2("Initial X11 packet contains bad byte order byte: 0x%x",
902 ucp[0]);
903 return -1;
904 }
905
906 /* Check if the whole packet is in buffer. */
907 if (buffer_len(b) <
908 12 + ((proto_len + 3) & ~3) + ((data_len + 3) & ~3))
909 return 0;
910
911 /* Check if authentication protocol matches. */
912 if (proto_len != strlen(x11_saved_proto) ||
913 memcmp(ucp + 12, x11_saved_proto, proto_len) != 0) {
914 debug2("X11 connection uses different authentication protocol.");
915 return -1;
916 }
917 /* Check if authentication data matches our fake data. */
918 if (data_len != x11_fake_data_len ||
919 memcmp(ucp + 12 + ((proto_len + 3) & ~3),
920 x11_fake_data, x11_fake_data_len) != 0) {
921 debug2("X11 auth data does not match fake data.");
922 return -1;
923 }
924 /* Check fake data length */
925 if (x11_fake_data_len != x11_saved_data_len) {
926 error("X11 fake_data_len %d != saved_data_len %d",
927 x11_fake_data_len, x11_saved_data_len);
928 return -1;
929 }
930 /*
931 * Received authentication protocol and data match
932 * our fake data. Substitute the fake data with real
933 * data.
934 */
935 memcpy(ucp + 12 + ((proto_len + 3) & ~3),
936 x11_saved_data, x11_saved_data_len);
937 return 1;
938 }
939
940 static void
941 channel_pre_x11_open_13(Channel *c, fd_set *readset, fd_set *writeset)
942 {
943 int ret = x11_open_helper(&c->output);
944
945 if (ret == 1) {
946 /* Start normal processing for the channel. */
947 c->type = SSH_CHANNEL_OPEN;
948 channel_pre_open_13(c, readset, writeset);
949 } else if (ret == -1) {
950 /*
951 * We have received an X11 connection that has bad
952 * authentication information.
953 */
954 logit("X11 connection rejected because of wrong authentication.");
955 buffer_clear(&c->input);
956 buffer_clear(&c->output);
957 channel_close_fd(&c->sock);
958 c->sock = -1;
959 c->type = SSH_CHANNEL_CLOSED;
960 packet_start(SSH_MSG_CHANNEL_CLOSE);
961 packet_put_int(c->remote_id);
962 packet_send();
963 }
964 }
965
966 static void
967 channel_pre_x11_open(Channel *c, fd_set *readset, fd_set *writeset)
968 {
969 int ret = x11_open_helper(&c->output);
970
971 /* c->force_drain = 1; */
972
973 if (ret == 1) {
974 c->type = SSH_CHANNEL_OPEN;
975 channel_pre_open(c, readset, writeset);
976 } else if (ret == -1) {
977 logit("X11 connection rejected because of wrong authentication.");
978 debug2("X11 rejected %d i%d/o%d", c->self, c->istate, c->ostate);
979 chan_read_failed(c);
980 buffer_clear(&c->input);
981 chan_ibuf_empty(c);
982 buffer_clear(&c->output);
983 /* for proto v1, the peer will send an IEOF */
984 if (compat20)
985 chan_write_failed(c);
986 else
987 c->type = SSH_CHANNEL_OPEN;
988 debug2("X11 closed %d i%d/o%d", c->self, c->istate, c->ostate);
989 }
990 }
991
992 /* try to decode a socks4 header */
993 /* ARGSUSED */
994 static int
995 channel_decode_socks4(Channel *c, fd_set *readset, fd_set *writeset)
996 {
997 char *p, *host;
998 u_int len, have, i, found, need;
999 char username[256];
1000 struct {
1001 u_int8_t version;
1002 u_int8_t command;
1003 u_int16_t dest_port;
1004 struct in_addr dest_addr;
1005 } s4_req, s4_rsp;
1006
1007 debug2("channel %d: decode socks4", c->self);
1008
1009 have = buffer_len(&c->input);
1010 len = sizeof(s4_req);
1011 if (have < len)
1012 return 0;
1013 p = buffer_ptr(&c->input);
1014
1015 need = 1;
1016 /* SOCKS4A uses an invalid IP address 0.0.0.x */
1017 if (p[4] == 0 && p[5] == 0 && p[6] == 0 && p[7] != 0) {
1018 debug2("channel %d: socks4a request", c->self);
1019 /* ... and needs an extra string (the hostname) */
1020 need = 2;
1021 }
1022 /* Check for terminating NUL on the string(s) */
1023 for (found = 0, i = len; i < have; i++) {
1024 if (p[i] == '\0') {
1025 found++;
1026 if (found == need)
1027 break;
1028 }
1029 if (i > 1024) {
1030 /* the peer is probably sending garbage */
1031 debug("channel %d: decode socks4: too long",
1032 c->self);
1033 return -1;
1034 }
1035 }
1036 if (found < need)
1037 return 0;
1038 buffer_get(&c->input, (char *)&s4_req.version, 1);
1039 buffer_get(&c->input, (char *)&s4_req.command, 1);
1040 buffer_get(&c->input, (char *)&s4_req.dest_port, 2);
1041 buffer_get(&c->input, (char *)&s4_req.dest_addr, 4);
1042 have = buffer_len(&c->input);
1043 p = buffer_ptr(&c->input);
1044 len = strlen(p);
1045 debug2("channel %d: decode socks4: user %s/%d", c->self, p, len);
1046 len++; /* trailing '\0' */
1047 if (len > have)
1048 fatal("channel %d: decode socks4: len %d > have %d",
1049 c->self, len, have);
1050 strlcpy(username, p, sizeof(username));
1051 buffer_consume(&c->input, len);
1052
1053 if (c->path != NULL) {
1054 xfree(c->path);
1055 c->path = NULL;
1056 }
1057 if (need == 1) { /* SOCKS4: one string */
1058 host = inet_ntoa(s4_req.dest_addr);
1059 c->path = xstrdup(host);
1060 } else { /* SOCKS4A: two strings */
1061 have = buffer_len(&c->input);
1062 p = buffer_ptr(&c->input);
1063 len = strlen(p);
1064 debug2("channel %d: decode socks4a: host %s/%d",
1065 c->self, p, len);
1066 len++; /* trailing '\0' */
1067 if (len > have)
1068 fatal("channel %d: decode socks4a: len %d > have %d",
1069 c->self, len, have);
1070 if (len > NI_MAXHOST) {
1071 error("channel %d: hostname \"%.100s\" too long",
1072 c->self, p);
1073 return -1;
1074 }
1075 c->path = xstrdup(p);
1076 buffer_consume(&c->input, len);
1077 }
1078 c->host_port = ntohs(s4_req.dest_port);
1079
1080 debug2("channel %d: dynamic request: socks4 host %s port %u command %u",
1081 c->self, c->path, c->host_port, s4_req.command);
1082
1083 if (s4_req.command != 1) {
1084 debug("channel %d: cannot handle: %s cn %d",
1085 c->self, need == 1 ? "SOCKS4" : "SOCKS4A", s4_req.command);
1086 return -1;
1087 }
1088 s4_rsp.version = 0; /* vn: 0 for reply */
1089 s4_rsp.command = 90; /* cd: req granted */
1090 s4_rsp.dest_port = 0; /* ignored */
1091 s4_rsp.dest_addr.s_addr = INADDR_ANY; /* ignored */
1092 buffer_append(&c->output, &s4_rsp, sizeof(s4_rsp));
1093 return 1;
1094 }
1095
1096 /* try to decode a socks5 header */
1097 #define SSH_SOCKS5_AUTHDONE 0x1000
1098 #define SSH_SOCKS5_NOAUTH 0x00
1099 #define SSH_SOCKS5_IPV4 0x01
1100 #define SSH_SOCKS5_DOMAIN 0x03
1101 #define SSH_SOCKS5_IPV6 0x04
1102 #define SSH_SOCKS5_CONNECT 0x01
1103 #define SSH_SOCKS5_SUCCESS 0x00
1104
1105 /* ARGSUSED */
1106 static int
1107 channel_decode_socks5(Channel *c, fd_set *readset, fd_set *writeset)
1108 {
1109 struct {
1110 u_int8_t version;
1111 u_int8_t command;
1112 u_int8_t reserved;
1113 u_int8_t atyp;
1114 } s5_req, s5_rsp;
1115 u_int16_t dest_port;
1116 u_char *p, dest_addr[255+1], ntop[INET6_ADDRSTRLEN];
1117 u_int have, need, i, found, nmethods, addrlen, af;
1118
1119 debug2("channel %d: decode socks5", c->self);
1120 p = buffer_ptr(&c->input);
1121 if (p[0] != 0x05)
1122 return -1;
1123 have = buffer_len(&c->input);
1124 if (!(c->flags & SSH_SOCKS5_AUTHDONE)) {
1125 /* format: ver | nmethods | methods */
1126 if (have < 2)
1127 return 0;
1128 nmethods = p[1];
1129 if (have < nmethods + 2)
1130 return 0;
1131 /* look for method: "NO AUTHENTICATION REQUIRED" */
1132 for (found = 0, i = 2; i < nmethods + 2; i++) {
1133 if (p[i] == SSH_SOCKS5_NOAUTH) {
1134 found = 1;
1135 break;
1136 }
1137 }
1138 if (!found) {
1139 debug("channel %d: method SSH_SOCKS5_NOAUTH not found",
1140 c->self);
1141 return -1;
1142 }
1143 buffer_consume(&c->input, nmethods + 2);
1144 buffer_put_char(&c->output, 0x05); /* version */
1145 buffer_put_char(&c->output, SSH_SOCKS5_NOAUTH); /* method */
1146 FD_SET(c->sock, writeset);
1147 c->flags |= SSH_SOCKS5_AUTHDONE;
1148 debug2("channel %d: socks5 auth done", c->self);
1149 return 0; /* need more */
1150 }
1151 debug2("channel %d: socks5 post auth", c->self);
1152 if (have < sizeof(s5_req)+1)
1153 return 0; /* need more */
1154 memcpy(&s5_req, p, sizeof(s5_req));
1155 if (s5_req.version != 0x05 ||
1156 s5_req.command != SSH_SOCKS5_CONNECT ||
1157 s5_req.reserved != 0x00) {
1158 debug2("channel %d: only socks5 connect supported", c->self);
1159 return -1;
1160 }
1161 switch (s5_req.atyp){
1162 case SSH_SOCKS5_IPV4:
1163 addrlen = 4;
1164 af = AF_INET;
1165 break;
1166 case SSH_SOCKS5_DOMAIN:
1167 addrlen = p[sizeof(s5_req)];
1168 af = -1;
1169 break;
1170 case SSH_SOCKS5_IPV6:
1171 addrlen = 16;
1172 af = AF_INET6;
1173 break;
1174 default:
1175 debug2("channel %d: bad socks5 atyp %d", c->self, s5_req.atyp);
1176 return -1;
1177 }
1178 need = sizeof(s5_req) + addrlen + 2;
1179 if (s5_req.atyp == SSH_SOCKS5_DOMAIN)
1180 need++;
1181 if (have < need)
1182 return 0;
1183 buffer_consume(&c->input, sizeof(s5_req));
1184 if (s5_req.atyp == SSH_SOCKS5_DOMAIN)
1185 buffer_consume(&c->input, 1); /* host string length */
1186 buffer_get(&c->input, (char *)&dest_addr, addrlen);
1187 buffer_get(&c->input, (char *)&dest_port, 2);
1188 dest_addr[addrlen] = '\0';
1189 if (c->path != NULL) {
1190 xfree(c->path);
1191 c->path = NULL;
1192 }
1193 if (s5_req.atyp == SSH_SOCKS5_DOMAIN) {
1194 if (addrlen >= NI_MAXHOST) {
1195 error("channel %d: dynamic request: socks5 hostname "
1196 "\"%.100s\" too long", c->self, dest_addr);
1197 return -1;
1198 }
1199 c->path = xstrdup(dest_addr);
1200 } else {
1201 if (inet_ntop(af, dest_addr, ntop, sizeof(ntop)) == NULL)
1202 return -1;
1203 c->path = xstrdup(ntop);
1204 }
1205 c->host_port = ntohs(dest_port);
1206
1207 debug2("channel %d: dynamic request: socks5 host %s port %u command %u",
1208 c->self, c->path, c->host_port, s5_req.command);
1209
1210 s5_rsp.version = 0x05;
1211 s5_rsp.command = SSH_SOCKS5_SUCCESS;
1212 s5_rsp.reserved = 0; /* ignored */
1213 s5_rsp.atyp = SSH_SOCKS5_IPV4;
1214 ((struct in_addr *)&dest_addr)->s_addr = INADDR_ANY;
1215 dest_port = 0; /* ignored */
1216
1217 buffer_append(&c->output, &s5_rsp, sizeof(s5_rsp));
1218 buffer_append(&c->output, &dest_addr, sizeof(struct in_addr));
1219 buffer_append(&c->output, &dest_port, sizeof(dest_port));
1220 return 1;
1221 }
1222
1223 /* dynamic port forwarding */
1224 static void
1225 channel_pre_dynamic(Channel *c, fd_set *readset, fd_set *writeset)
1226 {
1227 u_char *p;
1228 u_int have;
1229 int ret;
1230
1231 have = buffer_len(&c->input);
1232 debug2("channel %d: pre_dynamic: have %d", c->self, have);
1233 /* buffer_dump(&c->input); */
1234 /* check if the fixed size part of the packet is in buffer. */
1235 if (have < 3) {
1236 /* need more */
1237 FD_SET(c->sock, readset);
1238 return;
1239 }
1240 /* try to guess the protocol */
1241 p = buffer_ptr(&c->input);
1242 switch (p[0]) {
1243 case 0x04:
1244 ret = channel_decode_socks4(c, readset, writeset);
1245 break;
1246 case 0x05:
1247 ret = channel_decode_socks5(c, readset, writeset);
1248 break;
1249 default:
1250 ret = -1;
1251 break;
1252 }
1253 if (ret < 0) {
1254 chan_mark_dead(c);
1255 } else if (ret == 0) {
1256 debug2("channel %d: pre_dynamic: need more", c->self);
1257 /* need more */
1258 FD_SET(c->sock, readset);
1259 } else {
1260 /* switch to the next state */
1261 c->type = SSH_CHANNEL_OPENING;
1262 port_open_helper(c, "direct-tcpip");
1263 }
1264 }
1265
1266 /* This is our fake X11 server socket. */
1267 /* ARGSUSED */
1268 static void
1269 channel_post_x11_listener(Channel *c, fd_set *readset, fd_set *writeset)
1270 {
1271 Channel *nc;
1272 struct sockaddr_storage addr;
1273 int newsock;
1274 socklen_t addrlen;
1275 char buf[16384], *remote_ipaddr;
1276 int remote_port;
1277
1278 if (FD_ISSET(c->sock, readset)) {
1279 debug("X11 connection requested.");
1280 addrlen = sizeof(addr);
1281 newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen);
1282 if (c->single_connection) {
1283 debug2("single_connection: closing X11 listener.");
1284 channel_close_fd(&c->sock);
1285 chan_mark_dead(c);
1286 }
1287 if (newsock < 0) {
1288 error("accept: %.100s", strerror(errno));
1289 return;
1290 }
1291 set_nodelay(newsock);
1292 remote_ipaddr = get_peer_ipaddr(newsock);
1293 remote_port = get_peer_port(newsock);
1294 snprintf(buf, sizeof buf, "X11 connection from %.200s port %d",
1295 remote_ipaddr, remote_port);
1296
1297 nc = channel_new("accepted x11 socket",
1298 SSH_CHANNEL_OPENING, newsock, newsock, -1,
1299 c->local_window_max, c->local_maxpacket, 0, buf, 1);
1300 if (compat20) {
1301 packet_start(SSH2_MSG_CHANNEL_OPEN);
1302 packet_put_cstring("x11");
1303 packet_put_int(nc->self);
1304 packet_put_int(nc->local_window_max);
1305 packet_put_int(nc->local_maxpacket);
1306 /* originator ipaddr and port */
1307 packet_put_cstring(remote_ipaddr);
1308 if (datafellows & SSH_BUG_X11FWD) {
1309 debug2("ssh2 x11 bug compat mode");
1310 } else {
1311 packet_put_int(remote_port);
1312 }
1313 packet_send();
1314 } else {
1315 packet_start(SSH_SMSG_X11_OPEN);
1316 packet_put_int(nc->self);
1317 if (packet_get_protocol_flags() &
1318 SSH_PROTOFLAG_HOST_IN_FWD_OPEN)
1319 packet_put_cstring(buf);
1320 packet_send();
1321 }
1322 xfree(remote_ipaddr);
1323 }
1324 }
1325
1326 static void
1327 port_open_helper(Channel *c, char *rtype)
1328 {
1329 int direct;
1330 char buf[1024];
1331 char *remote_ipaddr = get_peer_ipaddr(c->sock);
1332 int remote_port = get_peer_port(c->sock);
1333
1334 direct = (strcmp(rtype, "direct-tcpip") == 0);
1335
1336 snprintf(buf, sizeof buf,
1337 "%s: listening port %d for %.100s port %d, "
1338 "connect from %.200s port %d",
1339 rtype, c->listening_port, c->path, c->host_port,
1340 remote_ipaddr, remote_port);
1341
1342 xfree(c->remote_name);
1343 c->remote_name = xstrdup(buf);
1344
1345 if (compat20) {
1346 packet_start(SSH2_MSG_CHANNEL_OPEN);
1347 packet_put_cstring(rtype);
1348 packet_put_int(c->self);
1349 packet_put_int(c->local_window_max);
1350 packet_put_int(c->local_maxpacket);
1351 if (direct) {
1352 /* target host, port */
1353 packet_put_cstring(c->path);
1354 packet_put_int(c->host_port);
1355 } else {
1356 /* listen address, port */
1357 packet_put_cstring(c->path);
1358 packet_put_int(c->listening_port);
1359 }
1360 /* originator host and port */
1361 packet_put_cstring(remote_ipaddr);
1362 packet_put_int((u_int)remote_port);
1363 packet_send();
1364 } else {
1365 packet_start(SSH_MSG_PORT_OPEN);
1366 packet_put_int(c->self);
1367 packet_put_cstring(c->path);
1368 packet_put_int(c->host_port);
1369 if (packet_get_protocol_flags() &
1370 SSH_PROTOFLAG_HOST_IN_FWD_OPEN)
1371 packet_put_cstring(c->remote_name);
1372 packet_send();
1373 }
1374 xfree(remote_ipaddr);
1375 }
1376
1377 static void
1378 channel_set_reuseaddr(int fd)
1379 {
1380 int on = 1;
1381
1382 /*
1383 * Set socket options.
1384 * Allow local port reuse in TIME_WAIT.
1385 */
1386 if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on)) == -1)
1387 error("setsockopt SO_REUSEADDR fd %d: %s", fd, strerror(errno));
1388 }
1389
1390 /*
1391 * This socket is listening for connections to a forwarded TCP/IP port.
1392 */
1393 /* ARGSUSED */
1394 static void
1395 channel_post_port_listener(Channel *c, fd_set *readset, fd_set *writeset)
1396 {
1397 Channel *nc;
1398 struct sockaddr_storage addr;
1399 int newsock, nextstate;
1400 socklen_t addrlen;
1401 char *rtype;
1402
1403 if (FD_ISSET(c->sock, readset)) {
1404 debug("Connection to port %d forwarding "
1405 "to %.100s port %d requested.",
1406 c->listening_port, c->path, c->host_port);
1407
1408 if (c->type == SSH_CHANNEL_RPORT_LISTENER) {
1409 nextstate = SSH_CHANNEL_OPENING;
1410 rtype = "forwarded-tcpip";
1411 } else {
1412 if (c->host_port == 0) {
1413 nextstate = SSH_CHANNEL_DYNAMIC;
1414 rtype = "dynamic-tcpip";
1415 } else {
1416 nextstate = SSH_CHANNEL_OPENING;
1417 rtype = "direct-tcpip";
1418 }
1419 }
1420
1421 addrlen = sizeof(addr);
1422 newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen);
1423 if (newsock < 0) {
1424 error("accept: %.100s", strerror(errno));
1425 return;
1426 }
1427 set_nodelay(newsock);
1428 nc = channel_new(rtype, nextstate, newsock, newsock, -1,
1429 c->local_window_max, c->local_maxpacket, 0, rtype, 1);
1430 nc->listening_port = c->listening_port;
1431 nc->host_port = c->host_port;
1432 if (c->path != NULL)
1433 nc->path = xstrdup(c->path);
1434
1435 if (nextstate != SSH_CHANNEL_DYNAMIC)
1436 port_open_helper(nc, rtype);
1437 }
1438 }
1439
1440 /*
1441 * This is the authentication agent socket listening for connections from
1442 * clients.
1443 */
1444 /* ARGSUSED */
1445 static void
1446 channel_post_auth_listener(Channel *c, fd_set *readset, fd_set *writeset)
1447 {
1448 Channel *nc;
1449 int newsock;
1450 struct sockaddr_storage addr;
1451 socklen_t addrlen;
1452
1453 if (FD_ISSET(c->sock, readset)) {
1454 addrlen = sizeof(addr);
1455 newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen);
1456 if (newsock < 0) {
1457 error("accept from auth socket: %.100s", strerror(errno));
1458 return;
1459 }
1460 nc = channel_new("accepted auth socket",
1461 SSH_CHANNEL_OPENING, newsock, newsock, -1,
1462 c->local_window_max, c->local_maxpacket,
1463 0, "accepted auth socket", 1);
1464 if (compat20) {
1465 packet_start(SSH2_MSG_CHANNEL_OPEN);
1466 packet_put_cstring("auth-agent@openssh.com");
1467 packet_put_int(nc->self);
1468 packet_put_int(c->local_window_max);
1469 packet_put_int(c->local_maxpacket);
1470 } else {
1471 packet_start(SSH_SMSG_AGENT_OPEN);
1472 packet_put_int(nc->self);
1473 }
1474 packet_send();
1475 }
1476 }
1477
1478 /* ARGSUSED */
1479 static void
1480 channel_post_connecting(Channel *c, fd_set *readset, fd_set *writeset)
1481 {
1482 int err = 0, sock;
1483 socklen_t sz = sizeof(err);
1484
1485 if (FD_ISSET(c->sock, writeset)) {
1486 if (getsockopt(c->sock, SOL_SOCKET, SO_ERROR, &err, &sz) < 0) {
1487 err = errno;
1488 error("getsockopt SO_ERROR failed");
1489 }
1490 if (err == 0) {
1491 debug("channel %d: connected to %s port %d",
1492 c->self, c->connect_ctx.host, c->connect_ctx.port);
1493 channel_connect_ctx_free(&c->connect_ctx);
1494 c->type = SSH_CHANNEL_OPEN;
1495 if (compat20) {
1496 packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
1497 packet_put_int(c->remote_id);
1498 packet_put_int(c->self);
1499 packet_put_int(c->local_window);
1500 packet_put_int(c->local_maxpacket);
1501 } else {
1502 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
1503 packet_put_int(c->remote_id);
1504 packet_put_int(c->self);
1505 }
1506 } else {
1507 debug("channel %d: connection failed: %s",
1508 c->self, strerror(err));
1509 /* Try next address, if any */
1510 if ((sock = connect_next(&c->connect_ctx)) > 0) {
1511 close(c->sock);
1512 c->sock = c->rfd = c->wfd = sock;
1513 channel_max_fd = channel_find_maxfd();
1514 return;
1515 }
1516 /* Exhausted all addresses */
1517 error("connect_to %.100s port %d: failed.",
1518 c->connect_ctx.host, c->connect_ctx.port);
1519 channel_connect_ctx_free(&c->connect_ctx);
1520 if (compat20) {
1521 packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE);
1522 packet_put_int(c->remote_id);
1523 packet_put_int(SSH2_OPEN_CONNECT_FAILED);
1524 if (!(datafellows & SSH_BUG_OPENFAILURE)) {
1525 packet_put_cstring(strerror(err));
1526 packet_put_cstring("");
1527 }
1528 } else {
1529 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
1530 packet_put_int(c->remote_id);
1531 }
1532 chan_mark_dead(c);
1533 }
1534 packet_send();
1535 }
1536 }
1537
1538 /* ARGSUSED */
1539 static int
1540 channel_handle_rfd(Channel *c, fd_set *readset, fd_set *writeset)
1541 {
1542 char buf[CHAN_RBUF];
1543 int len, force;
1544
1545 force = c->isatty && c->detach_close && c->istate != CHAN_INPUT_CLOSED;
1546 if (c->rfd != -1 && (force || FD_ISSET(c->rfd, readset))) {
1547 errno = 0;
1548 len = read(c->rfd, buf, sizeof(buf));
1549 if (len < 0 && (errno == EINTR ||
1550 ((errno == EAGAIN || errno == EWOULDBLOCK) && !force)))
1551 return 1;
1552 #ifndef PTY_ZEROREAD
1553 if (len <= 0) {
1554 #else
1555 if ((!c->isatty && len <= 0) ||
1556 (c->isatty && (len < 0 || (len == 0 && errno != 0)))) {
1557 #endif
1558 debug2("channel %d: read<=0 rfd %d len %d",
1559 c->self, c->rfd, len);
1560 if (c->type != SSH_CHANNEL_OPEN) {
1561 debug2("channel %d: not open", c->self);
1562 chan_mark_dead(c);
1563 return -1;
1564 } else if (compat13) {
1565 buffer_clear(&c->output);
1566 c->type = SSH_CHANNEL_INPUT_DRAINING;
1567 debug2("channel %d: input draining.", c->self);
1568 } else {
1569 chan_read_failed(c);
1570 }
1571 return -1;
1572 }
1573 if (c->input_filter != NULL) {
1574 if (c->input_filter(c, buf, len) == -1) {
1575 debug2("channel %d: filter stops", c->self);
1576 chan_read_failed(c);
1577 }
1578 } else if (c->datagram) {
1579 buffer_put_string(&c->input, buf, len);
1580 } else {
1581 buffer_append(&c->input, buf, len);
1582 }
1583 }
1584 return 1;
1585 }
1586
1587 /* ARGSUSED */
1588 static int
1589 channel_handle_wfd(Channel *c, fd_set *readset, fd_set *writeset)
1590 {
1591 struct termios tio;
1592 u_char *data = NULL, *buf;
1593 u_int dlen;
1594 int len;
1595
1596 /* Send buffered output data to the socket. */
1597 if (c->wfd != -1 &&
1598 FD_ISSET(c->wfd, writeset) &&
1599 buffer_len(&c->output) > 0) {
1600 if (c->output_filter != NULL) {
1601 if ((buf = c->output_filter(c, &data, &dlen)) == NULL) {
1602 debug2("channel %d: filter stops", c->self);
1603 if (c->type != SSH_CHANNEL_OPEN)
1604 chan_mark_dead(c);
1605 else
1606 chan_write_failed(c);
1607 return -1;
1608 }
1609 } else if (c->datagram) {
1610 buf = data = buffer_get_string(&c->output, &dlen);
1611 } else {
1612 buf = data = buffer_ptr(&c->output);
1613 dlen = buffer_len(&c->output);
1614 }
1615
1616 if (c->datagram) {
1617 /* ignore truncated writes, datagrams might get lost */
1618 c->local_consumed += dlen + 4;
1619 len = write(c->wfd, buf, dlen);
1620 xfree(data);
1621 if (len < 0 && (errno == EINTR || errno == EAGAIN ||
1622 errno == EWOULDBLOCK))
1623 return 1;
1624 if (len <= 0) {
1625 if (c->type != SSH_CHANNEL_OPEN)
1626 chan_mark_dead(c);
1627 else
1628 chan_write_failed(c);
1629 return -1;
1630 }
1631 return 1;
1632 }
1633 #ifdef _AIX
1634 /* XXX: Later AIX versions can't push as much data to tty */
1635 if (compat20 && c->wfd_isatty)
1636 dlen = MIN(dlen, 8*1024);
1637 #endif
1638
1639 len = write(c->wfd, buf, dlen);
1640 if (len < 0 &&
1641 (errno == EINTR || errno == EAGAIN || errno == EWOULDBLOCK))
1642 return 1;
1643 if (len <= 0) {
1644 if (c->type != SSH_CHANNEL_OPEN) {
1645 debug2("channel %d: not open", c->self);
1646 chan_mark_dead(c);
1647 return -1;
1648 } else if (compat13) {
1649 buffer_clear(&c->output);
1650 debug2("channel %d: input draining.", c->self);
1651 c->type = SSH_CHANNEL_INPUT_DRAINING;
1652 } else {
1653 chan_write_failed(c);
1654 }
1655 return -1;
1656 }
1657 #ifndef BROKEN_TCGETATTR_ICANON
1658 if (compat20 && c->isatty && dlen >= 1 && buf[0] != '\r') {
1659 if (tcgetattr(c->wfd, &tio) == 0 &&
1660 !(tio.c_lflag & ECHO) && (tio.c_lflag & ICANON)) {
1661 /*
1662 * Simulate echo to reduce the impact of
1663 * traffic analysis. We need to match the
1664 * size of a SSH2_MSG_CHANNEL_DATA message
1665 * (4 byte channel id + buf)
1666 */
1667 packet_send_ignore(4 + len);
1668 packet_send();
1669 }
1670 }
1671 #endif
1672 buffer_consume(&c->output, len);
1673 if (compat20 && len > 0) {
1674 c->local_consumed += len;
1675 }
1676 }
1677 return 1;
1678 }
1679
1680 static int
1681 channel_handle_efd(Channel *c, fd_set *readset, fd_set *writeset)
1682 {
1683 char buf[CHAN_RBUF];
1684 int len;
1685
1686 /** XXX handle drain efd, too */
1687 if (c->efd != -1) {
1688 if (c->extended_usage == CHAN_EXTENDED_WRITE &&
1689 FD_ISSET(c->efd, writeset) &&
1690 buffer_len(&c->extended) > 0) {
1691 len = write(c->efd, buffer_ptr(&c->extended),
1692 buffer_len(&c->extended));
1693 debug2("channel %d: written %d to efd %d",
1694 c->self, len, c->efd);
1695 if (len < 0 && (errno == EINTR || errno == EAGAIN ||
1696 errno == EWOULDBLOCK))
1697 return 1;
1698 if (len <= 0) {
1699 debug2("channel %d: closing write-efd %d",
1700 c->self, c->efd);
1701 channel_close_fd(&c->efd);
1702 } else {
1703 buffer_consume(&c->extended, len);
1704 c->local_consumed += len;
1705 }
1706 } else if (c->extended_usage == CHAN_EXTENDED_READ &&
1707 (c->detach_close || FD_ISSET(c->efd, readset))) {
1708 len = read(c->efd, buf, sizeof(buf));
1709 debug2("channel %d: read %d from efd %d",
1710 c->self, len, c->efd);
1711 if (len < 0 && (errno == EINTR || ((errno == EAGAIN ||
1712 errno == EWOULDBLOCK) && !c->detach_close)))
1713 return 1;
1714 if (len <= 0) {
1715 debug2("channel %d: closing read-efd %d",
1716 c->self, c->efd);
1717 channel_close_fd(&c->efd);
1718 } else {
1719 buffer_append(&c->extended, buf, len);
1720 }
1721 }
1722 }
1723 return 1;
1724 }
1725
1726 /* ARGSUSED */
1727 static int
1728 channel_handle_ctl(Channel *c, fd_set *readset, fd_set *writeset)
1729 {
1730 char buf[16];
1731 int len;
1732
1733 /* Monitor control fd to detect if the slave client exits */
1734 if (c->ctl_fd != -1 && FD_ISSET(c->ctl_fd, readset)) {
1735 len = read(c->ctl_fd, buf, sizeof(buf));
1736 if (len < 0 &&
1737 (errno == EINTR || errno == EAGAIN || errno == EWOULDBLOCK))
1738 return 1;
1739 if (len <= 0) {
1740 debug2("channel %d: ctl read<=0", c->self);
1741 if (c->type != SSH_CHANNEL_OPEN) {
1742 debug2("channel %d: not open", c->self);
1743 chan_mark_dead(c);
1744 return -1;
1745 } else {
1746 chan_read_failed(c);
1747 chan_write_failed(c);
1748 }
1749 return -1;
1750 } else
1751 fatal("%s: unexpected data on ctl fd", __func__);
1752 }
1753 return 1;
1754 }
1755
1756 static int
1757 channel_check_window(Channel *c)
1758 {
1759 if (c->type == SSH_CHANNEL_OPEN &&
1760 !(c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD)) &&
1761 ((c->local_window_max - c->local_window >
1762 c->local_maxpacket*3) ||
1763 c->local_window < c->local_window_max/2) &&
1764 c->local_consumed > 0) {
1765 packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
1766 packet_put_int(c->remote_id);
1767 packet_put_int(c->local_consumed);
1768 packet_send();
1769 debug2("channel %d: window %d sent adjust %d",
1770 c->self, c->local_window,
1771 c->local_consumed);
1772 c->local_window += c->local_consumed;
1773 c->local_consumed = 0;
1774 }
1775 return 1;
1776 }
1777
1778 static void
1779 channel_post_open(Channel *c, fd_set *readset, fd_set *writeset)
1780 {
1781 channel_handle_rfd(c, readset, writeset);
1782 channel_handle_wfd(c, readset, writeset);
1783 if (!compat20)
1784 return;
1785 channel_handle_efd(c, readset, writeset);
1786 channel_handle_ctl(c, readset, writeset);
1787 channel_check_window(c);
1788 }
1789
1790 /* ARGSUSED */
1791 static void
1792 channel_post_output_drain_13(Channel *c, fd_set *readset, fd_set *writeset)
1793 {
1794 int len;
1795
1796 /* Send buffered output data to the socket. */
1797 if (FD_ISSET(c->sock, writeset) && buffer_len(&c->output) > 0) {
1798 len = write(c->sock, buffer_ptr(&c->output),
1799 buffer_len(&c->output));
1800 if (len <= 0)
1801 buffer_clear(&c->output);
1802 else
1803 buffer_consume(&c->output, len);
1804 }
1805 }
1806
1807 static void
1808 channel_handler_init_20(void)
1809 {
1810 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open;
1811 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open;
1812 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1813 channel_pre[SSH_CHANNEL_RPORT_LISTENER] = &channel_pre_listener;
1814 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1815 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1816 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1817 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1818
1819 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open;
1820 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1821 channel_post[SSH_CHANNEL_RPORT_LISTENER] = &channel_post_port_listener;
1822 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1823 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1824 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1825 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open;
1826 }
1827
1828 static void
1829 channel_handler_init_13(void)
1830 {
1831 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open_13;
1832 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open_13;
1833 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1834 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1835 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1836 channel_pre[SSH_CHANNEL_INPUT_DRAINING] = &channel_pre_input_draining;
1837 channel_pre[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_pre_output_draining;
1838 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1839 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1840
1841 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open;
1842 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1843 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1844 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1845 channel_post[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_post_output_drain_13;
1846 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1847 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open;
1848 }
1849
1850 static void
1851 channel_handler_init_15(void)
1852 {
1853 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open;
1854 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open;
1855 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1856 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1857 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1858 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1859 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1860
1861 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1862 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1863 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1864 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open;
1865 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1866 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open;
1867 }
1868
1869 static void
1870 channel_handler_init(void)
1871 {
1872 int i;
1873
1874 for (i = 0; i < SSH_CHANNEL_MAX_TYPE; i++) {
1875 channel_pre[i] = NULL;
1876 channel_post[i] = NULL;
1877 }
1878 if (compat20)
1879 channel_handler_init_20();
1880 else if (compat13)
1881 channel_handler_init_13();
1882 else
1883 channel_handler_init_15();
1884 }
1885
1886 /* gc dead channels */
1887 static void
1888 channel_garbage_collect(Channel *c)
1889 {
1890 if (c == NULL)
1891 return;
1892 if (c->detach_user != NULL) {
1893 if (!chan_is_dead(c, c->detach_close))
1894 return;
1895 debug2("channel %d: gc: notify user", c->self);
1896 c->detach_user(c->self, NULL);
1897 /* if we still have a callback */
1898 if (c->detach_user != NULL)
1899 return;
1900 debug2("channel %d: gc: user detached", c->self);
1901 }
1902 if (!chan_is_dead(c, 1))
1903 return;
1904 debug2("channel %d: garbage collecting", c->self);
1905 channel_free(c);
1906 }
1907
1908 static void
1909 channel_handler(chan_fn *ftab[], fd_set *readset, fd_set *writeset)
1910 {
1911 static int did_init = 0;
1912 u_int i, oalloc;
1913 Channel *c;
1914
1915 if (!did_init) {
1916 channel_handler_init();
1917 did_init = 1;
1918 }
1919 for (i = 0, oalloc = channels_alloc; i < oalloc; i++) {
1920 c = channels[i];
1921 if (c == NULL)
1922 continue;
1923 if (c->delayed) {
1924 if (ftab == channel_pre)
1925 c->delayed = 0;
1926 else
1927 continue;
1928 }
1929 if (ftab[c->type] != NULL)
1930 (*ftab[c->type])(c, readset, writeset);
1931 channel_garbage_collect(c);
1932 }
1933 }
1934
1935 /*
1936 * Allocate/update select bitmasks and add any bits relevant to channels in
1937 * select bitmasks.
1938 */
1939 void
1940 channel_prepare_select(fd_set **readsetp, fd_set **writesetp, int *maxfdp,
1941 u_int *nallocp, int rekeying)
1942 {
1943 u_int n, sz, nfdset;
1944
1945 n = MAX(*maxfdp, channel_max_fd);
1946
1947 nfdset = howmany(n+1, NFDBITS);
1948 /* Explicitly test here, because xrealloc isn't always called */
1949 if (nfdset && SIZE_T_MAX / nfdset < sizeof(fd_mask))
1950 fatal("channel_prepare_select: max_fd (%d) is too large", n);
1951 sz = nfdset * sizeof(fd_mask);
1952
1953 /* perhaps check sz < nalloc/2 and shrink? */
1954 if (*readsetp == NULL || sz > *nallocp) {
1955 *readsetp = xrealloc(*readsetp, nfdset, sizeof(fd_mask));
1956 *writesetp = xrealloc(*writesetp, nfdset, sizeof(fd_mask));
1957 *nallocp = sz;
1958 }
1959 *maxfdp = n;
1960 memset(*readsetp, 0, sz);
1961 memset(*writesetp, 0, sz);
1962
1963 if (!rekeying)
1964 channel_handler(channel_pre, *readsetp, *writesetp);
1965 }
1966
1967 /*
1968 * After select, perform any appropriate operations for channels which have
1969 * events pending.
1970 */
1971 void
1972 channel_after_select(fd_set *readset, fd_set *writeset)
1973 {
1974 channel_handler(channel_post, readset, writeset);
1975 }
1976
1977
1978 /* If there is data to send to the connection, enqueue some of it now. */
1979 void
1980 channel_output_poll(void)
1981 {
1982 Channel *c;
1983 u_int i, len;
1984
1985 for (i = 0; i < channels_alloc; i++) {
1986 c = channels[i];
1987 if (c == NULL)
1988 continue;
1989
1990 /*
1991 * We are only interested in channels that can have buffered
1992 * incoming data.
1993 */
1994 if (compat13) {
1995 if (c->type != SSH_CHANNEL_OPEN &&
1996 c->type != SSH_CHANNEL_INPUT_DRAINING)
1997 continue;
1998 } else {
1999 if (c->type != SSH_CHANNEL_OPEN)
2000 continue;
2001 }
2002 if (compat20 &&
2003 (c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD))) {
2004 /* XXX is this true? */
2005 debug3("channel %d: will not send data after close", c->self);
2006 continue;
2007 }
2008
2009 /* Get the amount of buffered data for this channel. */
2010 if ((c->istate == CHAN_INPUT_OPEN ||
2011 c->istate == CHAN_INPUT_WAIT_DRAIN) &&
2012 (len = buffer_len(&c->input)) > 0) {
2013 if (c->datagram) {
2014 if (len > 0) {
2015 u_char *data;
2016 u_int dlen;
2017
2018 data = buffer_get_string(&c->input,
2019 &dlen);
2020 packet_start(SSH2_MSG_CHANNEL_DATA);
2021 packet_put_int(c->remote_id);
2022 packet_put_string(data, dlen);
2023 packet_send();
2024 c->remote_window -= dlen + 4;
2025 xfree(data);
2026 }
2027 continue;
2028 }
2029 /*
2030 * Send some data for the other side over the secure
2031 * connection.
2032 */
2033 if (compat20) {
2034 if (len > c->remote_window)
2035 len = c->remote_window;
2036 if (len > c->remote_maxpacket)
2037 len = c->remote_maxpacket;
2038 } else {
2039 if (packet_is_interactive()) {
2040 if (len > 1024)
2041 len = 512;
2042 } else {
2043 /* Keep the packets at reasonable size. */
2044 if (len > packet_get_maxsize()/2)
2045 len = packet_get_maxsize()/2;
2046 }
2047 }
2048 if (len > 0) {
2049 packet_start(compat20 ?
2050 SSH2_MSG_CHANNEL_DATA : SSH_MSG_CHANNEL_DATA);
2051 packet_put_int(c->remote_id);
2052 packet_put_string(buffer_ptr(&c->input), len);
2053 packet_send();
2054 buffer_consume(&c->input, len);
2055 c->remote_window -= len;
2056 }
2057 } else if (c->istate == CHAN_INPUT_WAIT_DRAIN) {
2058 if (compat13)
2059 fatal("cannot happen: istate == INPUT_WAIT_DRAIN for proto 1.3");
2060 /*
2061 * input-buffer is empty and read-socket shutdown:
2062 * tell peer, that we will not send more data: send IEOF.
2063 * hack for extended data: delay EOF if EFD still in use.
2064 */
2065 if (CHANNEL_EFD_INPUT_ACTIVE(c))
2066 debug2("channel %d: ibuf_empty delayed efd %d/(%d)",
2067 c->self, c->efd, buffer_len(&c->extended));
2068 else
2069 chan_ibuf_empty(c);
2070 }
2071 /* Send extended data, i.e. stderr */
2072 if (compat20 &&
2073 !(c->flags & CHAN_EOF_SENT) &&
2074 c->remote_window > 0 &&
2075 (len = buffer_len(&c->extended)) > 0 &&
2076 c->extended_usage == CHAN_EXTENDED_READ) {
2077 debug2("channel %d: rwin %u elen %u euse %d",
2078 c->self, c->remote_window, buffer_len(&c->extended),
2079 c->extended_usage);
2080 if (len > c->remote_window)
2081 len = c->remote_window;
2082 if (len > c->remote_maxpacket)
2083 len = c->remote_maxpacket;
2084 packet_start(SSH2_MSG_CHANNEL_EXTENDED_DATA);
2085 packet_put_int(c->remote_id);
2086 packet_put_int(SSH2_EXTENDED_DATA_STDERR);
2087 packet_put_string(buffer_ptr(&c->extended), len);
2088 packet_send();
2089 buffer_consume(&c->extended, len);
2090 c->remote_window -= len;
2091 debug2("channel %d: sent ext data %d", c->self, len);
2092 }
2093 }
2094 }
2095
2096
2097 /* -- protocol input */
2098
2099 /* ARGSUSED */
2100 void
2101 channel_input_data(int type, u_int32_t seq, void *ctxt)
2102 {
2103 int id;
2104 char *data;
2105 u_int data_len;
2106 Channel *c;
2107
2108 /* Get the channel number and verify it. */
2109 id = packet_get_int();
2110 c = channel_lookup(id);
2111 if (c == NULL)
2112 packet_disconnect("Received data for nonexistent channel %d.", id);
2113
2114 /* Ignore any data for non-open channels (might happen on close) */
2115 if (c->type != SSH_CHANNEL_OPEN &&
2116 c->type != SSH_CHANNEL_X11_OPEN)
2117 return;
2118
2119 /* Get the data. */
2120 data = packet_get_string_ptr(&data_len);
2121
2122 /*
2123 * Ignore data for protocol > 1.3 if output end is no longer open.
2124 * For protocol 2 the sending side is reducing its window as it sends
2125 * data, so we must 'fake' consumption of the data in order to ensure
2126 * that window updates are sent back. Otherwise the connection might
2127 * deadlock.
2128 */
2129 if (!compat13 && c->ostate != CHAN_OUTPUT_OPEN) {
2130 if (compat20) {
2131 c->local_window -= data_len;
2132 c->local_consumed += data_len;
2133 }
2134 return;
2135 }
2136
2137 if (compat20) {
2138 if (data_len > c->local_maxpacket) {
2139 logit("channel %d: rcvd big packet %d, maxpack %d",
2140 c->self, data_len, c->local_maxpacket);
2141 }
2142 if (data_len > c->local_window) {
2143 logit("channel %d: rcvd too much data %d, win %d",
2144 c->self, data_len, c->local_window);
2145 return;
2146 }
2147 c->local_window -= data_len;
2148 }
2149 if (c->datagram)
2150 buffer_put_string(&c->output, data, data_len);
2151 else
2152 buffer_append(&c->output, data, data_len);
2153 packet_check_eom();
2154 }
2155
2156 /* ARGSUSED */
2157 void
2158 channel_input_extended_data(int type, u_int32_t seq, void *ctxt)
2159 {
2160 int id;
2161 char *data;
2162 u_int data_len, tcode;
2163 Channel *c;
2164
2165 /* Get the channel number and verify it. */
2166 id = packet_get_int();
2167 c = channel_lookup(id);
2168
2169 if (c == NULL)
2170 packet_disconnect("Received extended_data for bad channel %d.", id);
2171 if (c->type != SSH_CHANNEL_OPEN) {
2172 logit("channel %d: ext data for non open", id);
2173 return;
2174 }
2175 if (c->flags & CHAN_EOF_RCVD) {
2176 if (datafellows & SSH_BUG_EXTEOF)
2177 debug("channel %d: accepting ext data after eof", id);
2178 else
2179 packet_disconnect("Received extended_data after EOF "
2180 "on channel %d.", id);
2181 }
2182 tcode = packet_get_int();
2183 if (c->efd == -1 ||
2184 c->extended_usage != CHAN_EXTENDED_WRITE ||
2185 tcode != SSH2_EXTENDED_DATA_STDERR) {
2186 logit("channel %d: bad ext data", c->self);
2187 return;
2188 }
2189 data = packet_get_string(&data_len);
2190 packet_check_eom();
2191 if (data_len > c->local_window) {
2192 logit("channel %d: rcvd too much extended_data %d, win %d",
2193 c->self, data_len, c->local_window);
2194 xfree(data);
2195 return;
2196 }
2197 debug2("channel %d: rcvd ext data %d", c->self, data_len);
2198 c->local_window -= data_len;
2199 buffer_append(&c->extended, data, data_len);
2200 xfree(data);
2201 }
2202
2203 /* ARGSUSED */
2204 void
2205 channel_input_ieof(int type, u_int32_t seq, void *ctxt)
2206 {
2207 int id;
2208 Channel *c;
2209
2210 id = packet_get_int();
2211 packet_check_eom();
2212 c = channel_lookup(id);
2213 if (c == NULL)
2214 packet_disconnect("Received ieof for nonexistent channel %d.", id);
2215 chan_rcvd_ieof(c);
2216
2217 /* XXX force input close */
2218 if (c->force_drain && c->istate == CHAN_INPUT_OPEN) {
2219 debug("channel %d: FORCE input drain", c->self);
2220 c->istate = CHAN_INPUT_WAIT_DRAIN;
2221 if (buffer_len(&c->input) == 0)
2222 chan_ibuf_empty(c);
2223 }
2224
2225 }
2226
2227 /* ARGSUSED */
2228 void
2229 channel_input_close(int type, u_int32_t seq, void *ctxt)
2230 {
2231 int id;
2232 Channel *c;
2233
2234 id = packet_get_int();
2235 packet_check_eom();
2236 c = channel_lookup(id);
2237 if (c == NULL)
2238 packet_disconnect("Received close for nonexistent channel %d.", id);
2239
2240 /*
2241 * Send a confirmation that we have closed the channel and no more
2242 * data is coming for it.
2243 */
2244 packet_start(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION);
2245 packet_put_int(c->remote_id);
2246 packet_send();
2247
2248 /*
2249 * If the channel is in closed state, we have sent a close request,
2250 * and the other side will eventually respond with a confirmation.
2251 * Thus, we cannot free the channel here, because then there would be
2252 * no-one to receive the confirmation. The channel gets freed when
2253 * the confirmation arrives.
2254 */
2255 if (c->type != SSH_CHANNEL_CLOSED) {
2256 /*
2257 * Not a closed channel - mark it as draining, which will
2258 * cause it to be freed later.
2259 */
2260 buffer_clear(&c->input);
2261 c->type = SSH_CHANNEL_OUTPUT_DRAINING;
2262 }
2263 }
2264
2265 /* proto version 1.5 overloads CLOSE_CONFIRMATION with OCLOSE */
2266 /* ARGSUSED */
2267 void
2268 channel_input_oclose(int type, u_int32_t seq, void *ctxt)
2269 {
2270 int id = packet_get_int();
2271 Channel *c = channel_lookup(id);
2272
2273 packet_check_eom();
2274 if (c == NULL)
2275 packet_disconnect("Received oclose for nonexistent channel %d.", id);
2276 chan_rcvd_oclose(c);
2277 }
2278
2279 /* ARGSUSED */
2280 void
2281 channel_input_close_confirmation(int type, u_int32_t seq, void *ctxt)
2282 {
2283 int id = packet_get_int();
2284 Channel *c = channel_lookup(id);
2285
2286 packet_check_eom();
2287 if (c == NULL)
2288 packet_disconnect("Received close confirmation for "
2289 "out-of-range channel %d.", id);
2290 if (c->type != SSH_CHANNEL_CLOSED)
2291 packet_disconnect("Received close confirmation for "
2292 "non-closed channel %d (type %d).", id, c->type);
2293 channel_free(c);
2294 }
2295
2296 /* ARGSUSED */
2297 void
2298 channel_input_open_confirmation(int type, u_int32_t seq, void *ctxt)
2299 {
2300 int id, remote_id;
2301 Channel *c;
2302
2303 id = packet_get_int();
2304 c = channel_lookup(id);
2305
2306 if (c==NULL || c->type != SSH_CHANNEL_OPENING)
2307 packet_disconnect("Received open confirmation for "
2308 "non-opening channel %d.", id);
2309 remote_id = packet_get_int();
2310 /* Record the remote channel number and mark that the channel is now open. */
2311 c->remote_id = remote_id;
2312 c->type = SSH_CHANNEL_OPEN;
2313
2314 if (compat20) {
2315 c->remote_window = packet_get_int();
2316 c->remote_maxpacket = packet_get_int();
2317 if (c->open_confirm) {
2318 debug2("callback start");
2319 c->open_confirm(c->self, c->open_confirm_ctx);
2320 debug2("callback done");
2321 }
2322 debug2("channel %d: open confirm rwindow %u rmax %u", c->self,
2323 c->remote_window, c->remote_maxpacket);
2324 }
2325 packet_check_eom();
2326 }
2327
2328 static char *
2329 reason2txt(int reason)
2330 {
2331 switch (reason) {
2332 case SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED:
2333 return "administratively prohibited";
2334 case SSH2_OPEN_CONNECT_FAILED:
2335 return "connect failed";
2336 case SSH2_OPEN_UNKNOWN_CHANNEL_TYPE:
2337 return "unknown channel type";
2338 case SSH2_OPEN_RESOURCE_SHORTAGE:
2339 return "resource shortage";
2340 }
2341 return "unknown reason";
2342 }
2343
2344 /* ARGSUSED */
2345 void
2346 channel_input_open_failure(int type, u_int32_t seq, void *ctxt)
2347 {
2348 int id, reason;
2349 char *msg = NULL, *lang = NULL;
2350 Channel *c;
2351
2352 id = packet_get_int();
2353 c = channel_lookup(id);
2354
2355 if (c==NULL || c->type != SSH_CHANNEL_OPENING)
2356 packet_disconnect("Received open failure for "
2357 "non-opening channel %d.", id);
2358 if (compat20) {
2359 reason = packet_get_int();
2360 if (!(datafellows & SSH_BUG_OPENFAILURE)) {
2361 msg = packet_get_string(NULL);
2362 lang = packet_get_string(NULL);
2363 }
2364 logit("channel %d: open failed: %s%s%s", id,
2365 reason2txt(reason), msg ? ": ": "", msg ? msg : "");
2366 if (msg != NULL)
2367 xfree(msg);
2368 if (lang != NULL)
2369 xfree(lang);
2370 }
2371 packet_check_eom();
2372 /* Schedule the channel for cleanup/deletion. */
2373 chan_mark_dead(c);
2374 }
2375
2376 /* ARGSUSED */
2377 void
2378 channel_input_window_adjust(int type, u_int32_t seq, void *ctxt)
2379 {
2380 Channel *c;
2381 int id;
2382 u_int adjust;
2383
2384 if (!compat20)
2385 return;
2386
2387 /* Get the channel number and verify it. */
2388 id = packet_get_int();
2389 c = channel_lookup(id);
2390
2391 if (c == NULL) {
2392 logit("Received window adjust for non-open channel %d.", id);
2393 return;
2394 }
2395 adjust = packet_get_int();
2396 packet_check_eom();
2397 debug2("channel %d: rcvd adjust %u", id, adjust);
2398 c->remote_window += adjust;
2399 }
2400
2401 /* ARGSUSED */
2402 void
2403 channel_input_port_open(int type, u_int32_t seq, void *ctxt)
2404 {
2405 Channel *c = NULL;
2406 u_short host_port;
2407 char *host, *originator_string;
2408 int remote_id;
2409
2410 remote_id = packet_get_int();
2411 host = packet_get_string(NULL);
2412 host_port = packet_get_int();
2413
2414 if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) {
2415 originator_string = packet_get_string(NULL);
2416 } else {
2417 originator_string = xstrdup("unknown (remote did not supply name)");
2418 }
2419 packet_check_eom();
2420 c = channel_connect_to(host, host_port,
2421 "connected socket", originator_string);
2422 xfree(originator_string);
2423 xfree(host);
2424 if (c == NULL) {
2425 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
2426 packet_put_int(remote_id);
2427 packet_send();
2428 } else
2429 c->remote_id = remote_id;
2430 }
2431
2432 /* ARGSUSED */
2433 void
2434 channel_input_status_confirm(int type, u_int32_t seq, void *ctxt)
2435 {
2436 Channel *c;
2437 struct channel_confirm *cc;
2438 int id;
2439
2440 /* Reset keepalive timeout */
2441 packet_set_alive_timeouts(0);
2442
2443 id = packet_get_int();
2444 packet_check_eom();
2445
2446 debug2("channel_input_status_confirm: type %d id %d", type, id);
2447
2448 if ((c = channel_lookup(id)) == NULL) {
2449 logit("channel_input_status_confirm: %d: unknown", id);
2450 return;
2451 }
2452 ;
2453 if ((cc = TAILQ_FIRST(&c->status_confirms)) == NULL)
2454 return;
2455 cc->cb(type, c, cc->ctx);
2456 TAILQ_REMOVE(&c->status_confirms, cc, entry);
2457 bzero(cc, sizeof(*cc));
2458 xfree(cc);
2459 }
2460
2461 /* -- tcp forwarding */
2462
2463 void
2464 channel_set_af(int af)
2465 {
2466 IPv4or6 = af;
2467 }
2468
2469 void
2470 channel_set_rdomain(int rdomain)
2471 {
2472 channel_rdomain = rdomain;
2473 }
2474
2475 static int
2476 channel_setup_fwd_listener(int type, const char *listen_addr,
2477 u_short listen_port, int *allocated_listen_port,
2478 const char *host_to_connect, u_short port_to_connect, int gateway_ports)
2479 {
2480 Channel *c;
2481 int sock, r, success = 0, wildcard = 0, is_client;
2482 struct addrinfo hints, *ai, *aitop;
2483 const char *host, *addr;
2484 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
2485 in_port_t *lport_p;
2486
2487 host = (type == SSH_CHANNEL_RPORT_LISTENER) ?
2488 listen_addr : host_to_connect;
2489 is_client = (type == SSH_CHANNEL_PORT_LISTENER);
2490
2491 if (host == NULL) {
2492 error("No forward host name.");
2493 return 0;
2494 }
2495 if (strlen(host) >= NI_MAXHOST) {
2496 error("Forward host name too long.");
2497 return 0;
2498 }
2499
2500 /*
2501 * Determine whether or not a port forward listens to loopback,
2502 * specified address or wildcard. On the client, a specified bind
2503 * address will always override gateway_ports. On the server, a
2504 * gateway_ports of 1 (``yes'') will override the client's
2505 * specification and force a wildcard bind, whereas a value of 2
2506 * (``clientspecified'') will bind to whatever address the client
2507 * asked for.
2508 *
2509 * Special-case listen_addrs are:
2510 *
2511 * "0.0.0.0" -> wildcard v4/v6 if SSH_OLD_FORWARD_ADDR
2512 * "" (empty string), "*" -> wildcard v4/v6
2513 * "localhost" -> loopback v4/v6
2514 */
2515 addr = NULL;
2516 if (listen_addr == NULL) {
2517 /* No address specified: default to gateway_ports setting */
2518 if (gateway_ports)
2519 wildcard = 1;
2520 } else if (gateway_ports || is_client) {
2521 if (((datafellows & SSH_OLD_FORWARD_ADDR) &&
2522 strcmp(listen_addr, "0.0.0.0") == 0 && is_client == 0) ||
2523 *listen_addr == '\0' || strcmp(listen_addr, "*") == 0 ||
2524 (!is_client && gateway_ports == 1))
2525 wildcard = 1;
2526 else if (strcmp(listen_addr, "localhost") != 0)
2527 addr = listen_addr;
2528 }
2529
2530 debug3("channel_setup_fwd_listener: type %d wildcard %d addr %s",
2531 type, wildcard, (addr == NULL) ? "NULL" : addr);
2532
2533 /*
2534 * getaddrinfo returns a loopback address if the hostname is
2535 * set to NULL and hints.ai_flags is not AI_PASSIVE
2536 */
2537 memset(&hints, 0, sizeof(hints));
2538 hints.ai_family = IPv4or6;
2539 hints.ai_flags = wildcard ? AI_PASSIVE : 0;
2540 hints.ai_socktype = SOCK_STREAM;
2541 snprintf(strport, sizeof strport, "%d", listen_port);
2542 if ((r = getaddrinfo(addr, strport, &hints, &aitop)) != 0) {
2543 if (addr == NULL) {
2544 /* This really shouldn't happen */
2545 packet_disconnect("getaddrinfo: fatal error: %s",
2546 ssh_gai_strerror(r));
2547 } else {
2548 error("channel_setup_fwd_listener: "
2549 "getaddrinfo(%.64s): %s", addr,
2550 ssh_gai_strerror(r));
2551 }
2552 return 0;
2553 }
2554 if (allocated_listen_port != NULL)
2555 *allocated_listen_port = 0;
2556 for (ai = aitop; ai; ai = ai->ai_next) {
2557 switch (ai->ai_family) {
2558 case AF_INET:
2559 lport_p = &((struct sockaddr_in *)ai->ai_addr)->
2560 sin_port;
2561 break;
2562 case AF_INET6:
2563 lport_p = &((struct sockaddr_in6 *)ai->ai_addr)->
2564 sin6_port;
2565 break;
2566 default:
2567 continue;
2568 }
2569 /*
2570 * If allocating a port for -R forwards, then use the
2571 * same port for all address families.
2572 */
2573 if (type == SSH_CHANNEL_RPORT_LISTENER && listen_port == 0 &&
2574 allocated_listen_port != NULL && *allocated_listen_port > 0)
2575 *lport_p = htons(*allocated_listen_port);
2576
2577 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop),
2578 strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
2579 error("channel_setup_fwd_listener: getnameinfo failed");
2580 continue;
2581 }
2582 /* Create a port to listen for the host. */
2583 sock = socket_rdomain(ai->ai_family, ai->ai_socktype,
2584 ai->ai_protocol, channel_rdomain);
2585 if (sock < 0) {
2586 /* this is no error since kernel may not support ipv6 */
2587 verbose("socket: %.100s", strerror(errno));
2588 continue;
2589 }
2590
2591 channel_set_reuseaddr(sock);
2592 if (ai->ai_family == AF_INET6)
2593 sock_set_v6only(sock);
2594
2595 debug("Local forwarding listening on %s port %s.",
2596 ntop, strport);
2597
2598 /* Bind the socket to the address. */
2599 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
2600 /* address can be in use ipv6 address is already bound */
2601 if (!ai->ai_next)
2602 error("bind: %.100s", strerror(errno));
2603 else
2604 verbose("bind: %.100s", strerror(errno));
2605
2606 close(sock);
2607 continue;
2608 }
2609 /* Start listening for connections on the socket. */
2610 if (listen(sock, SSH_LISTEN_BACKLOG) < 0) {
2611 error("listen: %.100s", strerror(errno));
2612 close(sock);
2613 continue;
2614 }
2615
2616 /*
2617 * listen_port == 0 requests a dynamically allocated port -
2618 * record what we got.
2619 */
2620 if (type == SSH_CHANNEL_RPORT_LISTENER && listen_port == 0 &&
2621 allocated_listen_port != NULL &&
2622 *allocated_listen_port == 0) {
2623 *allocated_listen_port = get_sock_port(sock, 1);
2624 debug("Allocated listen port %d",
2625 *allocated_listen_port);
2626 }
2627
2628 /* Allocate a channel number for the socket. */
2629 c = channel_new("port listener", type, sock, sock, -1,
2630 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT,
2631 0, "port listener", 1);
2632 c->path = xstrdup(host);
2633 c->host_port = port_to_connect;
2634 c->listening_port = listen_port;
2635 success = 1;
2636 }
2637 if (success == 0)
2638 error("channel_setup_fwd_listener: cannot listen to port: %d",
2639 listen_port);
2640 freeaddrinfo(aitop);
2641 return success;
2642 }
2643
2644 int
2645 channel_cancel_rport_listener(const char *host, u_short port)
2646 {
2647 u_int i;
2648 int found = 0;
2649
2650 for (i = 0; i < channels_alloc; i++) {
2651 Channel *c = channels[i];
2652
2653 if (c != NULL && c->type == SSH_CHANNEL_RPORT_LISTENER &&
2654 strcmp(c->path, host) == 0 && c->listening_port == port) {
2655 debug2("%s: close channel %d", __func__, i);
2656 channel_free(c);
2657 found = 1;
2658 }
2659 }
2660
2661 return (found);
2662 }
2663
2664 /* protocol local port fwd, used by ssh (and sshd in v1) */
2665 int
2666 channel_setup_local_fwd_listener(const char *listen_host, u_short listen_port,
2667 const char *host_to_connect, u_short port_to_connect, int gateway_ports)
2668 {
2669 return channel_setup_fwd_listener(SSH_CHANNEL_PORT_LISTENER,
2670 listen_host, listen_port, NULL, host_to_connect, port_to_connect,
2671 gateway_ports);
2672 }
2673
2674 /* protocol v2 remote port fwd, used by sshd */
2675 int
2676 channel_setup_remote_fwd_listener(const char *listen_address,
2677 u_short listen_port, int *allocated_listen_port, int gateway_ports)
2678 {
2679 return channel_setup_fwd_listener(SSH_CHANNEL_RPORT_LISTENER,
2680 listen_address, listen_port, allocated_listen_port,
2681 NULL, 0, gateway_ports);
2682 }
2683
2684 /*
2685 * Initiate forwarding of connections to port "port" on remote host through
2686 * the secure channel to host:port from local side.
2687 */
2688
2689 int
2690 channel_request_remote_forwarding(const char *listen_host, u_short listen_port,
2691 const char *host_to_connect, u_short port_to_connect)
2692 {
2693 int type, success = 0;
2694
2695 /* Record locally that connection to this host/port is permitted. */
2696 if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION)
2697 fatal("channel_request_remote_forwarding: too many forwards");
2698
2699 /* Send the forward request to the remote side. */
2700 if (compat20) {
2701 const char *address_to_bind;
2702 if (listen_host == NULL) {
2703 if (datafellows & SSH_BUG_RFWD_ADDR)
2704 address_to_bind = "127.0.0.1";
2705 else
2706 address_to_bind = "localhost";
2707 } else if (*listen_host == '\0' ||
2708 strcmp(listen_host, "*") == 0) {
2709 if (datafellows & SSH_BUG_RFWD_ADDR)
2710 address_to_bind = "0.0.0.0";
2711 else
2712 address_to_bind = "";
2713 } else
2714 address_to_bind = listen_host;
2715
2716 packet_start(SSH2_MSG_GLOBAL_REQUEST);
2717 packet_put_cstring("tcpip-forward");
2718 packet_put_char(1); /* boolean: want reply */
2719 packet_put_cstring(address_to_bind);
2720 packet_put_int(listen_port);
2721 packet_send();
2722 packet_write_wait();
2723 /* Assume that server accepts the request */
2724 success = 1;
2725 } else {
2726 packet_start(SSH_CMSG_PORT_FORWARD_REQUEST);
2727 packet_put_int(listen_port);
2728 packet_put_cstring(host_to_connect);
2729 packet_put_int(port_to_connect);
2730 packet_send();
2731 packet_write_wait();
2732
2733 /* Wait for response from the remote side. */
2734 type = packet_read();
2735 switch (type) {
2736 case SSH_SMSG_SUCCESS:
2737 success = 1;
2738 break;
2739 case SSH_SMSG_FAILURE:
2740 break;
2741 default:
2742 /* Unknown packet */
2743 packet_disconnect("Protocol error for port forward request:"
2744 "received packet type %d.", type);
2745 }
2746 }
2747 if (success) {
2748 permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host_to_connect);
2749 permitted_opens[num_permitted_opens].port_to_connect = port_to_connect;
2750 permitted_opens[num_permitted_opens].listen_port = listen_port;
2751 num_permitted_opens++;
2752 }
2753 return (success ? 0 : -1);
2754 }
2755
2756 /*
2757 * Request cancellation of remote forwarding of connection host:port from
2758 * local side.
2759 */
2760 void
2761 channel_request_rforward_cancel(const char *host, u_short port)
2762 {
2763 int i;
2764
2765 if (!compat20)
2766 return;
2767
2768 for (i = 0; i < num_permitted_opens; i++) {
2769 if (permitted_opens[i].host_to_connect != NULL &&
2770 permitted_opens[i].listen_port == port)
2771 break;
2772 }
2773 if (i >= num_permitted_opens) {
2774 debug("%s: requested forward not found", __func__);
2775 return;
2776 }
2777 packet_start(SSH2_MSG_GLOBAL_REQUEST);
2778 packet_put_cstring("cancel-tcpip-forward");
2779 packet_put_char(0);
2780 packet_put_cstring(host == NULL ? "" : host);
2781 packet_put_int(port);
2782 packet_send();
2783
2784 permitted_opens[i].listen_port = 0;
2785 permitted_opens[i].port_to_connect = 0;
2786 xfree(permitted_opens[i].host_to_connect);
2787 permitted_opens[i].host_to_connect = NULL;
2788 }
2789
2790 /*
2791 * This is called after receiving CHANNEL_FORWARDING_REQUEST. This initates
2792 * listening for the port, and sends back a success reply (or disconnect
2793 * message if there was an error).
2794 */
2795 int
2796 channel_input_port_forward_request(int is_root, int gateway_ports)
2797 {
2798 u_short port, host_port;
2799 int success = 0;
2800 char *hostname;
2801
2802 /* Get arguments from the packet. */
2803 port = packet_get_int();
2804 hostname = packet_get_string(NULL);
2805 host_port = packet_get_int();
2806
2807 #ifndef HAVE_CYGWIN
2808 /*
2809 * Check that an unprivileged user is not trying to forward a
2810 * privileged port.
2811 */
2812 if (port < IPPORT_RESERVED && !is_root)
2813 packet_disconnect(
2814 "Requested forwarding of port %d but user is not root.",
2815 port);
2816 if (host_port == 0)
2817 packet_disconnect("Dynamic forwarding denied.");
2818 #endif
2819
2820 /* Initiate forwarding */
2821 success = channel_setup_local_fwd_listener(NULL, port, hostname,
2822 host_port, gateway_ports);
2823
2824 /* Free the argument string. */
2825 xfree(hostname);
2826
2827 return (success ? 0 : -1);
2828 }
2829
2830 /*
2831 * Permits opening to any host/port if permitted_opens[] is empty. This is
2832 * usually called by the server, because the user could connect to any port
2833 * anyway, and the server has no way to know but to trust the client anyway.
2834 */
2835 void
2836 channel_permit_all_opens(void)
2837 {
2838 if (num_permitted_opens == 0)
2839 all_opens_permitted = 1;
2840 }
2841
2842 void
2843 channel_add_permitted_opens(char *host, int port)
2844 {
2845 if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION)
2846 fatal("channel_add_permitted_opens: too many forwards");
2847 debug("allow port forwarding to host %s port %d", host, port);
2848
2849 permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host);
2850 permitted_opens[num_permitted_opens].port_to_connect = port;
2851 num_permitted_opens++;
2852
2853 all_opens_permitted = 0;
2854 }
2855
2856 int
2857 channel_add_adm_permitted_opens(char *host, int port)
2858 {
2859 if (num_adm_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION)
2860 fatal("channel_add_adm_permitted_opens: too many forwards");
2861 debug("config allows port forwarding to host %s port %d", host, port);
2862
2863 permitted_adm_opens[num_adm_permitted_opens].host_to_connect
2864 = xstrdup(host);
2865 permitted_adm_opens[num_adm_permitted_opens].port_to_connect = port;
2866 return ++num_adm_permitted_opens;
2867 }
2868
2869 void
2870 channel_clear_permitted_opens(void)
2871 {
2872 int i;
2873
2874 for (i = 0; i < num_permitted_opens; i++)
2875 if (permitted_opens[i].host_to_connect != NULL)
2876 xfree(permitted_opens[i].host_to_connect);
2877 num_permitted_opens = 0;
2878 }
2879
2880 void
2881 channel_clear_adm_permitted_opens(void)
2882 {
2883 int i;
2884
2885 for (i = 0; i < num_adm_permitted_opens; i++)
2886 if (permitted_adm_opens[i].host_to_connect != NULL)
2887 xfree(permitted_adm_opens[i].host_to_connect);
2888 num_adm_permitted_opens = 0;
2889 }
2890
2891 void
2892 channel_print_adm_permitted_opens(void)
2893 {
2894 int i;
2895
2896 printf("permitopen");
2897 if (num_adm_permitted_opens == 0) {
2898 printf(" any\n");
2899 return;
2900 }
2901 for (i = 0; i < num_adm_permitted_opens; i++)
2902 if (permitted_adm_opens[i].host_to_connect != NULL)
2903 printf(" %s:%d", permitted_adm_opens[i].host_to_connect,
2904 permitted_adm_opens[i].port_to_connect);
2905 printf("\n");
2906 }
2907
2908 /* Try to start non-blocking connect to next host in cctx list */
2909 static int
2910 connect_next(struct channel_connect *cctx)
2911 {
2912 int sock, saved_errno;
2913 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
2914
2915 for (; cctx->ai; cctx->ai = cctx->ai->ai_next) {
2916 if (cctx->ai->ai_family != AF_INET &&
2917 cctx->ai->ai_family != AF_INET6)
2918 continue;
2919 if (getnameinfo(cctx->ai->ai_addr, cctx->ai->ai_addrlen,
2920 ntop, sizeof(ntop), strport, sizeof(strport),
2921 NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
2922 error("connect_next: getnameinfo failed");
2923 continue;
2924 }
2925 if ((sock = socket_rdomain(cctx->ai->ai_family,
2926 cctx->ai->ai_socktype, cctx->ai->ai_protocol,
2927 channel_rdomain)) == -1) {
2928 if (cctx->ai->ai_next == NULL)
2929 error("socket: %.100s", strerror(errno));
2930 else
2931 verbose("socket: %.100s", strerror(errno));
2932 continue;
2933 }
2934 if (set_nonblock(sock) == -1)
2935 fatal("%s: set_nonblock(%d)", __func__, sock);
2936 if (connect(sock, cctx->ai->ai_addr,
2937 cctx->ai->ai_addrlen) == -1 && errno != EINPROGRESS) {
2938 debug("connect_next: host %.100s ([%.100s]:%s): "
2939 "%.100s", cctx->host, ntop, strport,
2940 strerror(errno));
2941 saved_errno = errno;
2942 close(sock);
2943 errno = saved_errno;
2944 continue; /* fail -- try next */
2945 }
2946 debug("connect_next: host %.100s ([%.100s]:%s) "
2947 "in progress, fd=%d", cctx->host, ntop, strport, sock);
2948 cctx->ai = cctx->ai->ai_next;
2949 set_nodelay(sock);
2950 return sock;
2951 }
2952 return -1;
2953 }
2954
2955 static void
2956 channel_connect_ctx_free(struct channel_connect *cctx)
2957 {
2958 xfree(cctx->host);
2959 if (cctx->aitop)
2960 freeaddrinfo(cctx->aitop);
2961 bzero(cctx, sizeof(*cctx));
2962 cctx->host = NULL;
2963 cctx->ai = cctx->aitop = NULL;
2964 }
2965
2966 /* Return CONNECTING channel to remote host, port */
2967 static Channel *
2968 connect_to(const char *host, u_short port, char *ctype, char *rname)
2969 {
2970 struct addrinfo hints;
2971 int gaierr;
2972 int sock = -1;
2973 char strport[NI_MAXSERV];
2974 struct channel_connect cctx;
2975 Channel *c;
2976
2977 memset(&cctx, 0, sizeof(cctx));
2978 memset(&hints, 0, sizeof(hints));
2979 hints.ai_family = IPv4or6;
2980 hints.ai_socktype = SOCK_STREAM;
2981 snprintf(strport, sizeof strport, "%d", port);
2982 if ((gaierr = getaddrinfo(host, strport, &hints, &cctx.aitop)) != 0) {
2983 error("connect_to %.100s: unknown host (%s)", host,
2984 ssh_gai_strerror(gaierr));
2985 return NULL;
2986 }
2987
2988 cctx.host = xstrdup(host);
2989 cctx.port = port;
2990 cctx.ai = cctx.aitop;
2991
2992 if ((sock = connect_next(&cctx)) == -1) {
2993 error("connect to %.100s port %d failed: %s",
2994 host, port, strerror(errno));
2995 channel_connect_ctx_free(&cctx);
2996 return NULL;
2997 }
2998 c = channel_new(ctype, SSH_CHANNEL_CONNECTING, sock, sock, -1,
2999 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, rname, 1);
3000 c->connect_ctx = cctx;
3001 return c;
3002 }
3003
3004 Channel *
3005 channel_connect_by_listen_address(u_short listen_port, char *ctype, char *rname)
3006 {
3007 int i;
3008
3009 for (i = 0; i < num_permitted_opens; i++) {
3010 if (permitted_opens[i].host_to_connect != NULL &&
3011 permitted_opens[i].listen_port == listen_port) {
3012 return connect_to(
3013 permitted_opens[i].host_to_connect,
3014 permitted_opens[i].port_to_connect, ctype, rname);
3015 }
3016 }
3017 error("WARNING: Server requests forwarding for unknown listen_port %d",
3018 listen_port);
3019 return NULL;
3020 }
3021
3022 /* Check if connecting to that port is permitted and connect. */
3023 Channel *
3024 channel_connect_to(const char *host, u_short port, char *ctype, char *rname)
3025 {
3026 int i, permit, permit_adm = 1;
3027
3028 permit = all_opens_permitted;
3029 if (!permit) {
3030 for (i = 0; i < num_permitted_opens; i++)
3031 if (permitted_opens[i].host_to_connect != NULL &&
3032 permitted_opens[i].port_to_connect == port &&
3033 strcmp(permitted_opens[i].host_to_connect, host) == 0)
3034 permit = 1;
3035 }
3036
3037 if (num_adm_permitted_opens > 0) {
3038 permit_adm = 0;
3039 for (i = 0; i < num_adm_permitted_opens; i++)
3040 if (permitted_adm_opens[i].host_to_connect != NULL &&
3041 permitted_adm_opens[i].port_to_connect == port &&
3042 strcmp(permitted_adm_opens[i].host_to_connect, host)
3043 == 0)
3044 permit_adm = 1;
3045 }
3046
3047 if (!permit || !permit_adm) {
3048 logit("Received request to connect to host %.100s port %d, "
3049 "but the request was denied.", host, port);
3050 return NULL;
3051 }
3052 return connect_to(host, port, ctype, rname);
3053 }
3054
3055 void
3056 channel_send_window_changes(void)
3057 {
3058 u_int i;
3059 struct winsize ws;
3060
3061 for (i = 0; i < channels_alloc; i++) {
3062 if (channels[i] == NULL || !channels[i]->client_tty ||
3063 channels[i]->type != SSH_CHANNEL_OPEN)
3064 continue;
3065 if (ioctl(channels[i]->rfd, TIOCGWINSZ, &ws) < 0)
3066 continue;
3067 channel_request_start(i, "window-change", 0);
3068 packet_put_int((u_int)ws.ws_col);
3069 packet_put_int((u_int)ws.ws_row);
3070 packet_put_int((u_int)ws.ws_xpixel);
3071 packet_put_int((u_int)ws.ws_ypixel);
3072 packet_send();
3073 }
3074 }
3075
3076 /* -- X11 forwarding */
3077
3078 /*
3079 * Creates an internet domain socket for listening for X11 connections.
3080 * Returns 0 and a suitable display number for the DISPLAY variable
3081 * stored in display_numberp , or -1 if an error occurs.
3082 */
3083 int
3084 x11_create_display_inet(int x11_display_offset, int x11_use_localhost,
3085 int single_connection, u_int *display_numberp, int **chanids)
3086 {
3087 Channel *nc = NULL;
3088 int display_number, sock;
3089 u_short port;
3090 struct addrinfo hints, *ai, *aitop;
3091 char strport[NI_MAXSERV];
3092 int gaierr, n, num_socks = 0, socks[NUM_SOCKS];
3093
3094 if (chanids == NULL)
3095 return -1;
3096
3097 for (display_number = x11_display_offset;
3098 display_number < MAX_DISPLAYS;
3099 display_number++) {
3100 port = 6000 + display_number;
3101 memset(&hints, 0, sizeof(hints));
3102 hints.ai_family = IPv4or6;
3103 hints.ai_flags = x11_use_localhost ? 0: AI_PASSIVE;
3104 hints.ai_socktype = SOCK_STREAM;
3105 snprintf(strport, sizeof strport, "%d", port);
3106 if ((gaierr = getaddrinfo(NULL, strport, &hints, &aitop)) != 0) {
3107 error("getaddrinfo: %.100s", ssh_gai_strerror(gaierr));
3108 return -1;
3109 }
3110 for (ai = aitop; ai; ai = ai->ai_next) {
3111 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
3112 continue;
3113 sock = socket_rdomain(ai->ai_family, ai->ai_socktype,
3114 ai->ai_protocol, channel_rdomain);
3115 if (sock < 0) {
3116 if ((errno != EINVAL) && (errno != EAFNOSUPPORT)) {
3117 error("socket: %.100s", strerror(errno));
3118 freeaddrinfo(aitop);
3119 return -1;
3120 } else {
3121 debug("x11_create_display_inet: Socket family %d not supported",
3122 ai->ai_family);
3123 continue;
3124 }
3125 }
3126 if (ai->ai_family == AF_INET6)
3127 sock_set_v6only(sock);
3128 if (x11_use_localhost)
3129 channel_set_reuseaddr(sock);
3130 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
3131 debug2("bind port %d: %.100s", port, strerror(errno));
3132 close(sock);
3133
3134 for (n = 0; n < num_socks; n++) {
3135 close(socks[n]);
3136 }
3137 num_socks = 0;
3138 break;
3139 }
3140 socks[num_socks++] = sock;
3141 if (num_socks == NUM_SOCKS)
3142 break;
3143 }
3144 freeaddrinfo(aitop);
3145 if (num_socks > 0)
3146 break;
3147 }
3148 if (display_number >= MAX_DISPLAYS) {
3149 error("Failed to allocate internet-domain X11 display socket.");
3150 return -1;
3151 }
3152 /* Start listening for connections on the socket. */
3153 for (n = 0; n < num_socks; n++) {
3154 sock = socks[n];
3155 if (listen(sock, SSH_LISTEN_BACKLOG) < 0) {
3156 error("listen: %.100s", strerror(errno));
3157 close(sock);
3158 return -1;
3159 }
3160 }
3161
3162 /* Allocate a channel for each socket. */
3163 *chanids = xcalloc(num_socks + 1, sizeof(**chanids));
3164 for (n = 0; n < num_socks; n++) {
3165 sock = socks[n];
3166 nc = channel_new("x11 listener",
3167 SSH_CHANNEL_X11_LISTENER, sock, sock, -1,
3168 CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT,
3169 0, "X11 inet listener", 1);
3170 nc->single_connection = single_connection;
3171 (*chanids)[n] = nc->self;
3172 }
3173 (*chanids)[n] = -1;
3174
3175 /* Return the display number for the DISPLAY environment variable. */
3176 *display_numberp = display_number;
3177 return (0);
3178 }
3179
3180 static int
3181 connect_local_xsocket_path(const char *pathname)
3182 {
3183 int sock;
3184 struct sockaddr_un addr;
3185
3186 sock = socket(AF_UNIX, SOCK_STREAM, 0);
3187 if (sock < 0)
3188 error("socket: %.100s", strerror(errno));
3189 memset(&addr, 0, sizeof(addr));
3190 addr.sun_family = AF_UNIX;
3191 strlcpy(addr.sun_path, pathname, sizeof addr.sun_path);
3192 if (connect(sock, (struct sockaddr *)&addr, sizeof(addr)) == 0)
3193 return sock;
3194 close(sock);
3195 error("connect %.100s: %.100s", addr.sun_path, strerror(errno));
3196 return -1;
3197 }
3198
3199 static int
3200 connect_local_xsocket(u_int dnr)
3201 {
3202 char buf[1024];
3203 snprintf(buf, sizeof buf, _PATH_UNIX_X, dnr);
3204 return connect_local_xsocket_path(buf);
3205 }
3206
3207 int
3208 x11_connect_display(void)
3209 {
3210 u_int display_number;
3211 const char *display;
3212 char buf[1024], *cp;
3213 struct addrinfo hints, *ai, *aitop;
3214 char strport[NI_MAXSERV];
3215 int gaierr, sock = 0;
3216
3217 /* Try to open a socket for the local X server. */
3218 display = getenv("DISPLAY");
3219 if (!display) {
3220 error("DISPLAY not set.");
3221 return -1;
3222 }
3223 /*
3224 * Now we decode the value of the DISPLAY variable and make a
3225 * connection to the real X server.
3226 */
3227
3228 /* Check if the display is from launchd. */
3229 #ifdef __APPLE__
3230 if (strncmp(display, "/tmp/launch", 11) == 0) {
3231 sock = connect_local_xsocket_path(display);
3232 if (sock < 0)
3233 return -1;
3234
3235 /* OK, we now have a connection to the display. */
3236 return sock;
3237 }
3238 #endif
3239 /*
3240 * Check if it is a unix domain socket. Unix domain displays are in
3241 * one of the following formats: unix:d[.s], :d[.s], ::d[.s]
3242 */
3243 if (strncmp(display, "unix:", 5) == 0 ||
3244 display[0] == ':') {
3245 /* Connect to the unix domain socket. */
3246 if (sscanf(strrchr(display, ':') + 1, "%u", &display_number) != 1) {
3247 error("Could not parse display number from DISPLAY: %.100s",
3248 display);
3249 return -1;
3250 }
3251 /* Create a socket. */
3252 sock = connect_local_xsocket(display_number);
3253 if (sock < 0)
3254 return -1;
3255
3256 /* OK, we now have a connection to the display. */
3257 return sock;
3258 }
3259 /*
3260 * Connect to an inet socket. The DISPLAY value is supposedly
3261 * hostname:d[.s], where hostname may also be numeric IP address.
3262 */
3263 strlcpy(buf, display, sizeof(buf));
3264 cp = strchr(buf, ':');
3265 if (!cp) {
3266 error("Could not find ':' in DISPLAY: %.100s", display);
3267 return -1;
3268 }
3269 *cp = 0;
3270 /* buf now contains the host name. But first we parse the display number. */
3271 if (sscanf(cp + 1, "%u", &display_number) != 1) {
3272 error("Could not parse display number from DISPLAY: %.100s",
3273 display);
3274 return -1;
3275 }
3276
3277 /* Look up the host address */
3278 memset(&hints, 0, sizeof(hints));
3279 hints.ai_family = IPv4or6;
3280 hints.ai_socktype = SOCK_STREAM;
3281 snprintf(strport, sizeof strport, "%u", 6000 + display_number);
3282 if ((gaierr = getaddrinfo(buf, strport, &hints, &aitop)) != 0) {
3283 error("%.100s: unknown host. (%s)", buf,
3284 ssh_gai_strerror(gaierr));
3285 return -1;
3286 }
3287 for (ai = aitop; ai; ai = ai->ai_next) {
3288 /* Create a socket. */
3289 sock = socket_rdomain(ai->ai_family, ai->ai_socktype,
3290 ai->ai_protocol, channel_rdomain);
3291 if (sock < 0) {
3292 debug2("socket: %.100s", strerror(errno));
3293 continue;
3294 }
3295 /* Connect it to the display. */
3296 if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
3297 debug2("connect %.100s port %u: %.100s", buf,
3298 6000 + display_number, strerror(errno));
3299 close(sock);
3300 continue;
3301 }
3302 /* Success */
3303 break;
3304 }
3305 freeaddrinfo(aitop);
3306 if (!ai) {
3307 error("connect %.100s port %u: %.100s", buf, 6000 + display_number,
3308 strerror(errno));
3309 return -1;
3310 }
3311 set_nodelay(sock);
3312 return sock;
3313 }
3314
3315 /*
3316 * This is called when SSH_SMSG_X11_OPEN is received. The packet contains
3317 * the remote channel number. We should do whatever we want, and respond
3318 * with either SSH_MSG_OPEN_CONFIRMATION or SSH_MSG_OPEN_FAILURE.
3319 */
3320
3321 /* ARGSUSED */
3322 void
3323 x11_input_open(int type, u_int32_t seq, void *ctxt)
3324 {
3325 Channel *c = NULL;
3326 int remote_id, sock = 0;
3327 char *remote_host;
3328
3329 debug("Received X11 open request.");
3330
3331 remote_id = packet_get_int();
3332
3333 if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) {
3334 remote_host = packet_get_string(NULL);
3335 } else {
3336 remote_host = xstrdup("unknown (remote did not supply name)");
3337 }
3338 packet_check_eom();
3339
3340 /* Obtain a connection to the real X display. */
3341 sock = x11_connect_display();
3342 if (sock != -1) {
3343 /* Allocate a channel for this connection. */
3344 c = channel_new("connected x11 socket",
3345 SSH_CHANNEL_X11_OPEN, sock, sock, -1, 0, 0, 0,
3346 remote_host, 1);
3347 c->remote_id = remote_id;
3348 c->force_drain = 1;
3349 }
3350 xfree(remote_host);
3351 if (c == NULL) {
3352 /* Send refusal to the remote host. */
3353 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
3354 packet_put_int(remote_id);
3355 } else {
3356 /* Send a confirmation to the remote host. */
3357 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
3358 packet_put_int(remote_id);
3359 packet_put_int(c->self);
3360 }
3361 packet_send();
3362 }
3363
3364 /* dummy protocol handler that denies SSH-1 requests (agent/x11) */
3365 /* ARGSUSED */
3366 void
3367 deny_input_open(int type, u_int32_t seq, void *ctxt)
3368 {
3369 int rchan = packet_get_int();
3370
3371 switch (type) {
3372 case SSH_SMSG_AGENT_OPEN:
3373 error("Warning: ssh server tried agent forwarding.");
3374 break;
3375 case SSH_SMSG_X11_OPEN:
3376 error("Warning: ssh server tried X11 forwarding.");
3377 break;
3378 default:
3379 error("deny_input_open: type %d", type);
3380 break;
3381 }
3382 error("Warning: this is probably a break-in attempt by a malicious server.");
3383 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
3384 packet_put_int(rchan);
3385 packet_send();
3386 }
3387
3388 /*
3389 * Requests forwarding of X11 connections, generates fake authentication
3390 * data, and enables authentication spoofing.
3391 * This should be called in the client only.
3392 */
3393 void
3394 x11_request_forwarding_with_spoofing(int client_session_id, const char *disp,
3395 const char *proto, const char *data)
3396 {
3397 u_int data_len = (u_int) strlen(data) / 2;
3398 u_int i, value;
3399 char *new_data;
3400 int screen_number;
3401 const char *cp;
3402 u_int32_t rnd = 0;
3403
3404 if (x11_saved_display == NULL)
3405 x11_saved_display = xstrdup(disp);
3406 else if (strcmp(disp, x11_saved_display) != 0) {
3407 error("x11_request_forwarding_with_spoofing: different "
3408 "$DISPLAY already forwarded");
3409 return;
3410 }
3411
3412 cp = strchr(disp, ':');
3413 if (cp)
3414 cp = strchr(cp, '.');
3415 if (cp)
3416 screen_number = (u_int)strtonum(cp + 1, 0, 400, NULL);
3417 else
3418 screen_number = 0;
3419
3420 if (x11_saved_proto == NULL) {
3421 /* Save protocol name. */
3422 x11_saved_proto = xstrdup(proto);
3423 /*
3424 * Extract real authentication data and generate fake data
3425 * of the same length.
3426 */
3427 x11_saved_data = xmalloc(data_len);
3428 x11_fake_data = xmalloc(data_len);
3429 for (i = 0; i < data_len; i++) {
3430 if (sscanf(data + 2 * i, "%2x", &value) != 1)
3431 fatal("x11_request_forwarding: bad "
3432 "authentication data: %.100s", data);
3433 if (i % 4 == 0)
3434 rnd = arc4random();
3435 x11_saved_data[i] = value;
3436 x11_fake_data[i] = rnd & 0xff;
3437 rnd >>= 8;
3438 }
3439 x11_saved_data_len = data_len;
3440 x11_fake_data_len = data_len;
3441 }
3442
3443 /* Convert the fake data into hex. */
3444 new_data = tohex(x11_fake_data, data_len);
3445
3446 /* Send the request packet. */
3447 if (compat20) {
3448 channel_request_start(client_session_id, "x11-req", 0);
3449 packet_put_char(0); /* XXX bool single connection */
3450 } else {
3451 packet_start(SSH_CMSG_X11_REQUEST_FORWARDING);
3452 }
3453 packet_put_cstring(proto);
3454 packet_put_cstring(new_data);
3455 packet_put_int(screen_number);
3456 packet_send();
3457 packet_write_wait();
3458 xfree(new_data);
3459 }
3460
3461
3462 /* -- agent forwarding */
3463
3464 /* Sends a message to the server to request authentication fd forwarding. */
3465
3466 void
3467 auth_request_forwarding(void)
3468 {
3469 packet_start(SSH_CMSG_AGENT_REQUEST_FORWARDING);
3470 packet_send();
3471 packet_write_wait();
3472 }
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